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AOA2 is a rare progressive adolescent-onset disease characterised by cerebellar vermis atrophy, peripheral neuropathy and elevated serum alpha-fetoprotein (AFP) caused by pathogenic bi-allelic variants in SETX, encoding senataxin, involved in DNA repair and RNA maturation. Sanger sequencing of genomic DNA, co-segregation and oxidative stress functional studies were performed in Family 1. Trio whole-exome sequencing (WES), followed by SETX RNA and qRT-PCR analysis, were performed in Family 2. Sanger sequencing in Family 1 revealed two novel in-frame SETX deletion and duplication variants in trans (c.7009_7011del; p.Val2337del and c.7369_7371dup; p.His2457dup). Patients had increased induced chromosomal aberrations at baseline and following exposure to higher mitomycin-C concentration and increased sensitivity to oxidative stress at the lower mitomycin-C concentration in cell viability test. Trio WES in Family 2 revealed two novel SETX variants in trans, a nonsense variant (c.568C T; p.Gln190*), and a deep intronic variant (c.5549-107A G). Intronic variant analysis and SETX mRNA expression revealed activation of a cryptic exon introducing a premature stop codon (p.Met1850Lysfs*18) and resulting in aberrant splicing, as shown by qRT-PCR analysis, thus leading to higher levels of cryptic exon activation. Along with a second deleterious allele, this variant leads to low levels of SETX mRNA and disease manifestations. Our report expands the phenotypic spectrum of AOA2. Results provide initial support for the hypomorphic nature of the novel in-frame deletion and duplication variants in Family 1. Deep-intronic variant analysis of Family 2 variants potentially reveals a previously undescribed poison exon in the SETX gene, which may contribute to tailored therapy development.

Objective To investigate the genetic basis of the recessive form of primary familial brain calcification and study pathways linking a novel gene with known dominant genes that cause the disease. Methods Whole exome sequencing and Sanger‐based segregation analysis were used to identify possible disease causing mutations. Mutation pathogenicity was validated by structural protein modeling. Functional associations between the candidate gene, MYORG, and genes previously implicated in the disease were examined through phylogenetic profiling. Results We studied nine affected individuals from two unrelated families of Middle Eastern origin. The median age of symptom onset was 29.5 years (range 21–57 years) and dysarthria was the most common presenting symptom. We identified in the MYORG gene, a homozygous c.1233delC mutation in one family and c.1060_1062delGAC mutation in another. The first mutation results in protein truncation and the second in deletion of a highly conserved aspartic acid that is likely to disrupt binding of the protein with its substrate. Phylogenetic profiling analysis of the MYORG protein sequence suggests co‐evolution with a number of calcium channels as well as other proteins related to regulation of anion transmembrane transport (False Discovery Rate, FDR < 10−8) and with PDCD6IP, a protein interacting with PDGFR β which is known to be involved in the disease. Interpretation MYORG mutations are linked to a recessive form of primary familial brain calcification. This association was recently described in patients of Chinese ancestry. We suggest the possibility that MYORG mutations lead to calcification in a PDGFR β‐related pathway.

Objectives Chromosomal microarray analysis is effectively applied prenatally to detect copy number changes. Single nucleotide polymorphism (SNP) probes included in the microarray platform can detect regions of excessive homozygosity and identical-by-descent genomic stretches. The utility of the latter as part of prenatal diagnosis is not well established. Recessive founder mutations are well recognized within distinct ethnic groups. Combining these data with prenatal sonography provides accurate focused molecular diagnoses quickly. We aimed to evaluate the application of this approach in expectant families presenting to our unit. Methods Three unrelated gravidae presenting with specific fetal sonographic findings: (1) ventriculomegaly with encephalocele; (2) severe polyhydramnion; and (3) enlarged echogenic kidneys, underwent amniocentesis for chromosomal microarray analysis, and genome-wide human SNP array was used to analyze DNA from amniocytes. The Genomic Oligoarray and SNP array evaluation tool v3.0© was used to detect recessive loci associated with the reported clinical findings. Candidate genes were further interrogated using the Israeli National Genetic Database (INGD) and specifically searching and identifying a corresponding founder mutation within the defined ethnic group. Results Three fetuses from 3 distinct nuclear families in which the parents shared a similar ethnicity (either Ashkenazi or Bukharan Jews) albeit no reported consanguinity were assessed. We found no copy number changes; however, by evaluating regions of homozygosity, we were able to reveal relevant candidate gene for the specific phenotype for each fetus. Using the INGD led to targeted testing of a specific homozygous fetal mutation for which parents were found to be carriers. In the fetus with ventriculomegaly with encephalocele c.1167dupA mutation in the FKTN gene, in the fetus with severe polyhydramnion c.167ins6[TTTCCC] mutation in the BSND gene, and in the fetus with enlarged echogenic kidneys, c.3761_3762delCCinsG in the PKHD1 gene were identified. Conclusions A tripartite approach integrating sonographic pathology with regions of excessive homozygosity data and INGD-based founder mutation repository yields a comprehensive streamlined approach to provide accurate genetic diagnosis and counselling within the time constraints of an ongoing pregnancy.

Purpose Usher syndrome (USH) is the most common cause for deaf-blindness. It is genetically and clinically heterogeneous and prevalent in populations with high consanguinity rate. We aim to characterize the set of genes and mutations that cause USH in the Israeli and Palestinian populations. Methods Seventy-four families with USH were recruited (23 with USH type 1 [USH1], 33 with USH2, seven with USH3, four with atypical USH, and seven families with an undetermined USH type). All affected subjects underwent a full ocular evaluation. A comprehensive genetic analysis, including Sanger sequencing for the detection of founder mutations, homozygosity mapping, and whole exome sequencing in large families was performed. Results In 79% of the families (59 out of 74), an autosomal recessive inheritance pattern could be determined. Mutation detection analysis led to the identification of biallelic causative mutations in 51 (69%) of the families, including 21 families with mutations in USH2A, 17 in MYO7A, and seven in CLRN1. Our analysis revealed 28 mutations, 11 of which are novel (including c.802G>A, c.8558+1G>T, c.10211del, and c.14023A>T in USH2A; c.285+2T>G, c.2187+1G>T, c.3892G>A, c.5069_5070insC, c.5101C>T, and c.6196C>T in MYO7A; and c.15494del in GPR98). Conclusions We report here novel homozygous mutations in various genes causing USH, extending the spectrum of causative mutations. We also prove combined sequencing techniques as useful tools to identify novel disease-causing mutations. To the best of our knowledge, this is the largest report of a genetic analysis of Israeli and Palestinian families (n = 74) with different USH subtypes.

Background Heterozygous germline mutations in any of the mismatch repair (MMR) genes, MLH1, MSH2, MSH6, and PMS2, cause Lynch syndrome (LS), an autosomal dominant cancer predisposition syndrome conferring a high risk of colorectal, endometrial, and other cancers in adulthood. Offspring of couples where both spouses have LS have a 1:4 risk of inheriting biallelic MMR gene mutations. These cause constitutional MMR deficiency (CMMRD) syndrome, a severe recessively inherited cancer syndrome with a broad tumor spectrum including mainly hematological malignancies, brain tumors, and colon cancer in childhood and adolescence. Many CMMRD children also present with cafe au lait spots and axillary freckling mimicking neurofibromatosis type 1. Procedure We describe our experience in seven CMMRD families demonstrating the role and importance of founder mutations and consanguinity on its prevalence. Clinical presentations included brain tumors, colon cancer, lymphoma, and small bowel cancer. Results In children from two nonconsanguineous Ashkenazi Jewish (AJ) families, the common Ashkenazi founder mutations were detected; these were homozygous in one family and compound heterozygous in the other. In four consanguineous families of various ancestries, different homozygous mutations were identified. In a nonconsanguineous Caucasus/AJ family, lack of PMS2 was demonstrated in tumor and normal tissues; however, mutations were not identified. Conclusions CMMRD is rare, but, especially in areas where founder mutations for LS and consanguinity are common, pediatricians should be aware of it since they are the first to encounter these children. Early diagnosis will enable tailored cancer surveillance in the entire family and a discussion regarding prenatal genetic diagnosis.

Pelizaeus-Merzbacher disease is an X-linked hypomyelinating leukodystrophy caused by mutations or rearrangements in PLP1. It presents in infancy with nystagmus, jerky head movements, hypotonia and developmental delay evolving into spastic tetraplegia with optic atrophy and variable movement disorders. A clinically similar phenotype caused by recessive mutations in GJC2 is known as Pelizaeus-Merzbacher-like disease. Both genes encode proteins associated with myelin. We describe three siblings of a consanguineous family manifesting the typical infantile-onset Pelizaeus-Merzbacher disease-like phenotype slowly evolving into a form of complicated hereditary spastic paraplegia with mental retardation, dysarthria, optic atrophy and peripheral neuropathy in adulthood. Magnetic resonance imaging and spectroscopy were consistent with a demyelinating leukodystrophy. Using genetic linkage and exome sequencing, we identified a homozygous missense c.399C>G; p.S133R mutation in MAG. This gene, previously associated with hereditary spastic paraplegia, encodes myelin-associated glycoprotein, which is involved in myelin maintenance and glia-axon interaction. This mutation is predicted to destabilize the protein and affect its tertiary structure. Examination of the sural nerve biopsy sample obtained in childhood in the oldest sibling revealed complete absence of myelin-associated glycoprotein accompanied by ill-formed onion-bulb structures and a relatively thin myelin sheath of the affected axons. Immunofluorescence, cell surface labelling, biochemical analysis and mass spectrometry-based proteomics studies in a variety of cell types demonstrated a devastating effect of the mutation on post-translational processing, steady state expression and subcellular localization of myelin-associated glycoprotein. In contrast to the wild-type protein, the p.S133R mutant was retained in the endoplasmic reticulum and was subjected to endoplasmic reticulum-associated protein degradation by the proteasome. Our findings identify involvement of myelin-associated glycoprotein in this family with a disorder affecting the central and peripheral nervous system, and suggest that loss of the protein function is responsible for the unique clinical phenotype.

Hereditary mixed polyposis syndrome is a rare colon cancer predisposition syndrome caused by a duplication of a non-coding sequence near the gremlin 1, DAN family BMP antagonist gene (GREM1) originally described in Ashkenazi Jews. Few families with GREM1 duplications have been described, so there are many questions about detection and management. We report 4 extended families with the duplication near GREM1 previously found in Ashkenazi Jews; 3 families were identified at cancer genetic clinics in Israel and 1 family was identified in a cohort of patients with familial colorectal cancer. Their clinical features include extra-colonic tumors, onset of polyps in adolescence, and rapid progression of some polyps to advanced adenomas. One family met diagnostic criteria for Lynch syndrome. Expansion of the hereditary mixed polyposis syndrome phenotype can inform surveillance strategies for carriers of GREM1 duplications.

Diagnosis of Lynch syndrome (LS) may be complex. Knowledge of mutation spectrum and founder mutations in specific populations facilitates the diagnostic process. Aim of the study is to describe genetic features of LS in the Israeli population and report novel and founder mutations. Patients were studied at high-risk clinics. Diagnostics followed a multi-step process, including tumor testing, gene analysis and testing for founder mutations. LS was defined by positive mutation testing. We diagnosed LS in 242 subjects from 113 families coming from different ethnicities. We identified 54 different mutations; 13 of them are novel. Sixty-seven (59%) families had mutations in MSH2, 20 (18%) in MSH6, 19 (17%) in MLH1 and 7 (6%) in PMS2; 27% of the MSH2 mutations were large deletions. Seven founder mutations were detected in 61/113 (54%) families. Constitutional mismatch repair deficiency (CMMR-D) was identified in five families. Gene distribution in the Israeli population is unique, with relatively high incidence of mutations in MSH2 and MSH6. The mutation spectrum is wide; however, 54% of cases are caused by one of seven founder mutations. CMMR-D occurs in the context of founder mutations and consanguinity. These features should guide the diagnostic process, risk estimation, and genetic counseling.

International audience; The hereditary spastic paraplegias (HSPs) are a clinically and genetically heterogeneous group of neurodegenerative diseases characterised by progressive spasticity in the lower limbs. The nosology of autosomal recessive forms is complex as most mapped loci have been identified in only one or a few families and account for only a small percentage of patients. We used next-generation sequencing focused on the SPG30 chromosomal region on chromosome 2q37.3 in two patients from the original linked family. In addition, wide genome scan and candidate gene analysis were performed in a second family of Palestinian origin. We identified a single homozygous mutation, p.R350G, that was found to cosegregate with the disease in the SPG30 kindred and was absent in 970 control chromosomes while affecting a strongly conserved amino acid at the end of the motor domain of KIF1A. Homozygosity and linkage mapping followed by mutation screening of KIF1A allowed us to identify a second mutation, p.A255V, in the second family. Comparison of the clinical features with the nature of the mutations of all reported KIF1A families, including those reported recently with hereditary sensory and autonomic neuropathy, suggests phenotype-genotype correlations that may help to understand the mechanisms involved in motor neuron degeneration. We have shown that mutations in the KIF1A gene are responsible for SPG30 in two autosomal recessive HSP families. In published families, the nature of the KIF1A mutations seems to be of good predictor of the underlying phenotype and vice versa.

Founder mutations in BRCA1/2 genes have been detected in several Jewish communities in Israel, including in Ashkenazi Jews and Jews who immigrated to Israel from Iraq, Yemen, Iran and Afghanistan. We analyzed DNA samples of patients of Sephardic origin (descendents of Jews from the Iberian Peninsula) with breast cancer (BC) and/or ovarian cancer (OC) and additional family history of these cancers. In this study we identified 2 mutations: p.A1708E in BRCA1 and c.67 + 1G > A (IVS2 + 1G > A) in BRCA2, each in 3 unrelated patients. The frequency of the two mutations was 26–31% among Sephardic high risk families and about 3% among the full cohort of 177 patients of this origin who were tested in our center. Based on haplotype analysis we concluded that these mutations are most probably founder mutations in Sephardic Jews. We recommend testing the two mutations in women of Sephardic origin who apply for BRCA testing because of personal and/or family history of BC and/or OC. Furthermore, we suggest adding them to the 5 mutations included in “The Jewish panel” of BRCA1/2 mutations that are being tested in Israel.

Nablus mask-like facial syndrome (NMFLS) is a rare microdeletion syndrome with a mask-like facial appearance as the most characteristic feature. In 2000, Teebi, was the first to report on a 4 years old boy affected with NMFLS. Since then two additional patients have been reported. Three years later, with the development of the array CGH technology, Shieh et al., elucidated the etiology of NMFLS by showing that the two patients studied share a similar to 4 Mb microdeletion in the long arm of chromosome 8 (q21.3-q22.1). Here we report on two NMFLS patients among which the first patient described by Teebi in 2000, and present newly described clinical findings including the common happy behaviour of the children. Array CGH analysis of these two patients permitted to reveal a deletion in the same region, 8q21.3-q22.1. Combining the available literature and our data, we were able to narrow the common deleted region to 2.78 Mb (93.56-96.34 Mb) in 8q22.1. Direct relations between the clinical findings with (one of) the genes in the critical region have to await further studies on NFMLS patients with overlapping or smaller deletions. (C) 2009 Elsevier Masson SAS. All rights reserved.

The H syndrome is a recently reported autosomal-recessive disorder characterized by cutaneous hyperpigmentation, hypertrichosis, hepatosplenomegaly, heart anomalies, hearing loss, hypogonadism, short stature, hallux valgus, and fixed flexion contractures of the toe joints and the proximal interphalangeal joints. Homozygosity mapping in five consanguineous families resulted in the identification of mutations in the SLC29A3 gene, which encodes the equilibrative nucleoside transporter hENT3. Three mutations were found in 11 families of Arab and Bulgarian origin. The finding of several different mutations in a small geographic region implies that the H syndrome might be rather common. The identification of mutations in the SLC29A3 gene in patients with a mild clinical phenotype suggests that this is a largely underdiagnosed condition and strongly suggests that even oligosymptomatic individuals might have the disorder.

Objective Congenital lipoid adrenal hyperplasia is an autosomal recessive condition due to mutations in Steroidogenic Acute Regulatory Protein (StAR) associated with the inability to synthesize all adrenal and gonadal steroids, resulting in adrenal insufficiency and failure to develop male genitalia in affected 46,XY individuals. We used two independent methods of prenatal diagnosis for CLAH. Method CLAH was diagnosed prenatally by measuring amniotic fluid estriol, adrenal, and gonadal hormone levels, and by mutation analysis for the c.201–202 delCT mutation in StAR. Results Prenatal testing diagnosed one affected and three unaffected fetuses in two families at risk for CLAH. Conclusion Prenatal testing for CLAH is effective, and targeted molecular genetic analysis should be considered in Palestinian families with a fetus with discordant 46,XY karyotype and female genitalia on ultrasound, and low maternal serum estriol. Copyright © 2007 John Wiley & Sons, Ltd.

Congenital lipoid adrenal hyperplasia (CLAH), caused by mutations in steroidogenic acute regulatory protein (StAR), is most frequent in Japanese and Palestinians. We report eight Palestinians from four unrelated families with CLAH.The objective of the study was to identify the mutation(s) in StAR, correlate genotype with phenotype, and determine whether the common mutation represents a founder mutation.Clinical, histopathological, and molecular genetic characterization was performed in these eight patients.All affected individuals (three XY, five XX) presented neonatally with undetectable adrenocortical hormones and are responding to replacement therapy. Only two sisters had neurodevelopmental deficits. Histopathological findings of excised XY gonads included accumulation of fat in Leydig cells. Significantly, already at 1 yr of age, positive placental alkaline phosphatase and octamer binding transcription factor staining indicated neoplastic potential. Sequence analysis of StAR revealed homozygosity for c.201_202delCT mutation in all eight cases, causing premature termination of the StAR protein. This mutation was confirmed to be a founder mutation using both an intragenic microsatellite and several single nucleotide polymorphism markers. Screening of 100 normal Jerusalem Palestinians detected no carriers of this mutation.CLAH is rare in the general Palestinian population. In most Palestinian cases, a founder c.201_202delCT mutation in StAR is the cause. The observed early neonatal presentation may reflect the major StAR protein truncation caused by this mutation. A crucial role for StAR in the central nervous system was not supported with normal neurological examinations in six of eight cases. Finally, we advocate early gonadectomy in XY CLAH cases, given the early onset of neoplastic changes observed histologically.

Autosomal recessive polycystic kidney disease (ARPKD) is usually detected late in pregnancies in embryos with large echogenic kidneys accompanied by oligohydramnios. Hundreds of private pathogenic variants have been identified in the large PKHD1 gene in various populations. Yet, because of the large size of the gene, segregation analysis of microsatellite polymorphic markers residing in the PKDH1 locus has commonly been utilized for prenatal diagnosis. Keeping in mind the limitations of this strategy, we utilized it for testing 7 families with affected fetuses or newborns, of which in 5 at least one parent was Ashkenazi, and identified that the same haplotype was shared by the majority of the Ashkenazi parents (7/9). This led us to suspect that they carry the same founder mutation. Whole Exome analysis of DNA from a fetus of one of the families detected an already known pathogenic variant c.3761_3762delCCinsG, an indel variant resulting in frameshift (p.Ala1254GlyfsX49). This variant was detected in 9 parents (5 families), of them 7 individuals were Ashkenazi and one Moroccan Jew who shared the same haplotype, and one Ashkenazi, who carried the same variant on a recombinant haplotype. Screening for this variant in 364 Ashkenazi individuals detected 2 carriers. These findings suggest that although c.3761_3762delCCinsG is considered one of the frequent variants detected in unrelated individuals, and was thought to have occurred independently on various haplotypes, it is in fact a founder mutation in the Ashkenazi population.

Heterozygous germline mutations in any of the mismatch repair (MMR) genes, MLH1, MSH2, MSH6, and PMS2, cause Lynch syndrome (LS), an autosomal dominant cancer predisposition syndrome conferring a high risk of colorectal, endometrial, and other cancers in adulthood. Offspring of couples where both spouses have LS have a 1:4 risk of inheriting biallelic MMR gene mutations. These cause constitutional MMR deficiency (CMMRD) syndrome, a severe recessively inherited cancer syndrome with a broad tumor spectrum including mainly hematological malignancies, brain tumors, and colon cancer in childhood and adolescence. Many CMMRD children also present with café au lait spots and axillary freckling mimicking neurofibromatosis type 1.We describe our experience in seven CMMRD families demonstrating the role and importance of founder mutations and consanguinity on its prevalence. Clinical presentations included brain tumors, colon cancer, lymphoma, and small bowel cancer.In children from two nonconsanguineous Ashkenazi Jewish (AJ) families, the common Ashkenazi founder mutations were detected; these were homozygous in one family and compound heterozygous in the other. In four consanguineous families of various ancestries, different homozygous mutations were identified. In a nonconsanguineous Caucasus/AJ family, lack of PMS2 was demonstrated in tumor and normal tissues; however, mutations were not identified.CMMRD is rare, but, especially in areas where founder mutations for LS and consanguinity are common, pediatricians should be aware of it since they are the first to encounter these children. Early diagnosis will enable tailored cancer surveillance in the entire family and a discussion regarding prenatal genetic diagnosis.

Retinoblastoma (Rb) is a childhood tumor (~1 in 20,000 live births) developing in the retina due to mutations in the RB1 gene. Identification of the oncogenic mutations in the RB1 gene is important for the clinical management and for genetic counseling to families with a child or a parent affected with the tumor. Here we present our experience in detecting the pathogenic mutations in blood samples, from 150 unrelated Rb patients and highlight the relevant counseling issues. Mutation screening in the RB1 gene was based on Sanger sequencing, mosaicism of recurrent CpG transition mutations was detected by allele specific PCR and multiplex ligation dependent probe amplification for detecting of large deletions/duplications. The overall detection rate of mutations in our cohort was 55 % (82/150). In the familial cases it was 100 % (17/17), in bilateral and unilateral-multifocal sporadic cases 91 % (50/55), and in the unilateral sporadic cases 19 % (15/78). Nonsense mutations and small deletions or insertions that results in transcripts with premature termination codons that are subject to nonsense mediated decay were the most frequent, detected in 50/82 (61 %) of the patients. The rest were large deletions detected in 14/82 (17 %), splice site mutations detected in 11/82 (13 %), missense mutations in four patients and mutations in the promoter sequence in three patients. Mutation mosaicism ranging from 10 to 30 % was detected by allele specific PCR in ten patients, 9 % (5/55) of patients with bilateral tumor and 33 % (5/15) of the patients with unilateral tumor. In three patients rare variants were detected as the only finding which was also detected in other healthy family members. Allele specific amplification of recurrent mutations raises in our cohort the identification rate from 82 to 91 % in the sporadic bilateral cases and from 13 to 19 % in the unilateral sporadic cases. Most mosaic cases could not be identified by Sanger sequencing and therefore screening for recurrent CpG transition mutations by allele specific amplification is of utmost importance. Molecular screening is important for the genetic counseling regarding the risk for tumor development and the relevance for prenatal diagnosis but in several families is accompanied by detecting rare variants that might be rare polymorphisms or low penetrant mutations.

Importance We describe a deep intronic mutation in adult polyglucosan body disease. Similar mechanisms can also explain manifesting heterozygous cases in other inborn metabolic diseases. Objective To explain the genetic change consistently associated with manifesting heterozygous patients with adult polyglucosan body disease. Design, Setting, and Participants This retrospective study took place from November 8, 2012, to November 7, 2014. We studied 35 typical patients with adult polyglucosan body disease, of whom 16 were heterozygous for the well-known c.986A>C mutation in the glycogen branching enzyme gene (GBE1) but harbored no other known mutation in 16 exons. Main Outcomes and Measures All 16 manifesting heterozygous patients had lower glycogen branching activity compared with homozygous patients, which showed inactivation of the apparently normal allele. We studied the messenger ribonucleic acid (mRNA) structure and the genetic change due to the elusive second mutation. Results When we reverse transcribed and sequenced the mRNA ofGBE1, we found that all manifesting heterozygous patients had the c.986A>C mutant mRNA and complete lack of mRNA encoded by the second allele. We identified a deep intronic mutation in this allele,GBE1-IVS15 + 5289_5297delGTGTGGTGGinsTGTTTTTTACATGACAGGT, which acts as a gene trap, creating an ectopic last exon. The mRNA transcript from this allele missed the exon 16 and 3′UTR and encoded abnormal GBE causing further decrease of enzyme activity from 18% to 8%. Conclusions and Relevance We identified the deep intronic mutation, which acts as a gene trap. This second-most common adult polyglucosan body disease mutation explains another founder effect in all Ashkenazi-Jewish cases.

Objective: To present the clinical, molecular, and cell biological findings in a family with an autosomal recessive form of hereditary spastic paraplegia characterized by a combination of spastic paraplegia, optic atrophy, and peripheral neuropathy (SPOAN). Methods: We used a combination of whole-genome linkage analysis and exome sequencing to map the disease locus and to identify the responsible gene. To analyze the physiologic consequences of the disease, we used biochemical and cell biological methods. Results: Ten members of a highly consanguineous family manifested a childhood-onset SPOAN-like phenotype with slow progression into late adulthood. We mapped this disorder to a locus on chromosome 1q and identified a homozygous donor splice-site mutation in the IBA57 gene, previously implicated in 2 infants with lethal perinatal encephalomyopathy. This gene encodes the mitochondrial iron-sulfur (Fe/S) protein assembly factor IBA57. In addition to a severely decreased amount of normal IBA57 messenger RNA, a patient9s cells expressed an aberrantly spliced messenger RNA with a premature stop codon. Lymphoblasts contained 10-fold–lower levels of wild-type, but no signs of truncated IBA57 protein. The decrease in functional IBA57 resulted in reduced levels and activities of several mitochondrial [4Fe-4S] proteins, including complexes I and II, while mitochondrial [2Fe-2S] proteins remained normal. Conclusions: Our findings reinforce the suggested specific function of IBA57 in mitochondrial [4Fe-4S] protein maturation and provide additional evidence for its role in human disease. The less decreased IBA57 protein level in this family explains phenotypic differences compared with the previously described lethal encephalomyopathy with no functional IBA57.

The microphthalmia with linear skin defects syndrome (MLS, or MIDAS) is an X-linked dominant male-lethal disorder almost invariably associated with segmental monosomy of the Xp22 region. In two female patients, from two families, with MLS and a normal karyotype, we identified heterozygous de novo point mutations--a missense mutation (p.R217C) and a nonsense mutation (p.R197X)--in the HCCS gene. HCCS encodes the mitochondrial holocytochrome c-type synthase that functions as heme lyase by covalently adding the prosthetic heme group to both apocytochrome c and c(1). We investigated a third family, displaying phenotypic variability, in which the mother and two of her daughters carry an 8.6-kb submicroscopic deletion encompassing part of the HCCS gene. Functional analysis demonstrates that both mutant proteins (R217C and Delta 197-268) were unable to complement a Saccharomyces cerevisiae mutant deficient for the HCCS orthologue Cyc3p, in contrast to wild-type HCCS. Moreover, ectopically expressed HCCS wild-type and the R217C mutant protein are targeted to mitochondria in CHO-K1 cells, whereas the C-terminal-truncated Delta 197-268 mutant failed to be sorted to mitochondria. Cytochrome c, the final product of holocytochrome c-type synthase activity, is implicated in both oxidative phosphorylation (OXPHOS) and apoptosis. We hypothesize that the inability of HCCS-deficient cells to undergo cytochrome c-mediated apoptosis may push cell death toward necrosis that gives rise to severe deterioration of the affected tissues. In summary, we suggest that disturbance of both OXPHOS and the balance between apoptosis and necrosis, as well as the X-inactivation pattern, may contribute to the variable phenotype observed in patients with MLS.

We have diagnosed a boy with cystic fibrosis (CF) due to paternal UPD presenting with overweight and developmental delay, not typical features to CF patients. Two previously reported patients with paternal UPD(7) did not present overgrowth. The discrepancy between the phenotype of this boy and the other two patients raises the question of imprinted genes or homozygotization of a disease-causing gene in paternal UPD7.

A four-generation family was studied in which nine children had congenital cerebral palsy (CP), characterized by quadriplegia and mental retardation. All the affected children were born to healthy, related fathers, whereas the children of their healthy female relatives were unaffected. Linkage analysis attributed the condition to chromosome 9p24.3, where a 225 kb deletion was identified. The deletion spans a single gene, ANKRD15 (ankyrin repeat domain 15), which is ubiquitously expressed. In the affected children, the ANKRD15 is not expressed in lymphoblastoid cells, whereas in their healthy fathers, who harbor the same deletion, the expression of ANKRD15 did not deviate from controls. This expression pattern can be interpreted as a maternal imprinted gene that is expressed only from the paternal allele. The expression of ANKRD15 in lymphoblastoid cells from the control group was monoallelic but not imprinted. The monoallelic expression was restricted to the ANKRD15 gene, whereas biallelic expression was found in the DOCK8 gene, which resides at the telomeric side of the deletion. No correlation was found between the expression of the ANKRD15 gene and the pattern of DNA methylation in the CpG islands 5' of the gene. However, differences in methylation pattern were found in the CpG islands flanking the DMRT1 gene, which is located at the 3' side of the ANKRD15 gene. In the affected individuals, as in the control group, the CpG islands were hypo-methylated, whereas in the healthy fathers, the CpG islands were hyper-methylated in cis with the deletion. This unique family demonstrates a phenomenon of a deletion that creates imprinting-like inheritance. The implication of this family to sporadic CP is discussed.

Glycine encephalopathy (GE) (non-ketotic hyperglycinemia) is an autosomal recessive neurometabolic disease caused by defective activity of the glycine cleavage system. Clinically, patients present usually in the neonatal period with hypotonia, encephalopathy, hiccups and breath arrests with or without overt seizures. GE is considered rare, but its incidence is relatively high in several geographical areas around the world. We report a novel mutation causing GE in six extended Arab families, all from a small suburban village (population 5,000). A methionine to threonine change in the initiation codon of the glycine decarboxylase gene led to markedly reduced glycine decarboxylase mRNA levels and abolished glycine cleavage system activity.

We describe two pairs of siblings from a consanguineous family manifesting autosomal recessive hereditary spastic paraplegia caused by a novel mutation in the EXOSC3 gene, previously reported in pontocerebellar hypoplasia type 1. Clinical findings included delayed motor milestones, early-onset spastic paraplegia, variable cognitive disability, and cerebellar signs. Cerebral imaging demonstrated enlarged cisterna magna and mild hypoplasia and atrophy of the lower vermis with a normal pons. Genetic analysis using homozygosity mapping followed by whole exome sequencing identified homozygous c.571G>T; p.G191C mutation in the EXOSC3 gene. We suggest that EXOSC3 mutations may present not only as pontocerebellar hypoplasia type 1, but also as a complicated form of hereditary spastic paraplegia without pontine hypoplasia or atrophy.

Twenty-seven unrelated Jewish Ashkenazi patients with nonsyndromic prelingual deafness (NSD) were analyzed for mutations in the coding sequence of the connexin 26 (Cx26) gene. Biallelic mutations were identified in 19 of the 27 patients (70.4%); 12 were homozygous for the mutation 167delT, 2 were homozygous for the mutation 35delG, and 5 were compound 167delT/35delG heterozygotes. In addition three patients were heterozygous with no second identified mutation in the Cx26 gene. Biallelic mutations in the Cx26 gene account for 83% of familial cases and 44% of the sporadic cases. Among 268 unselected Ashkenazi individuals, 20 were 167delT/N heterozygotes, giving an estimate of 7.5% carrier frequency. Based on the 167delT carrier frequency in three studies (including the present one), it is expected that 167delT/167delT homozygotes account for 70% of all patients with NSD (1 in 1300). The hearing capacity of 30 patients (probands and their sibs) with biallelic Cx26 mutations and at least one allele with 167delT demonstrated inter- and intrafamilial variability from profound to mild hearing impairment.

Objectives: Carriers of the mutations 185delAG and 5382insC in the BRCA1 gene and 6174delT in the BRCA2 gene have a substantial life-time risk for breast and ovarian cancers (BC and OC). The aim of the study was to identify the clinical features and the hormonal risk modifiers in mutation carriers and the implication in suggested guidelines for treatment decisions in BRCA1/2 carrier patients. Study design: Breast and/or ovarian cancer patients from the Oncology and Cancer Genetic clinics were tested for the three Ashkenazi founder mutations: 87 patients were identified as carriers of one of these mutations. Clinical presentation and age at onset were correlated with the mutations, in patients with bilateral BC or BC and OC, the length of time that elapsed between the diagnosis of the two cancers was recorded. We compared BC and OC patients with regard to ages at menarche, first pregnancy and menopause, number of pregnancies and deliveries, the use of oral contraceptives, hormonal replacement therapy and fertility treatments. Results: The carriers of the three BRCA1/2 Ashkenazi founder mutations did not differ in clinical presentation nor age at onset. Forty-three patients (74.1%) of 58 BC patients were diagnosed between the ages 30 and 50, only four (6.9%) patients were diagnosed after age 60. Of BC patients diagnosed before age 35, 63.6% developed second BC as compared to 25.5% of those diagnosed after age 35. Ovarian cancer was diagnosed after age 45 in 89.7% of the patients, only one patient was diagnosed under the age of 40. Oral contraceptives use was documented in 61.3% of BC patients as compared to 11.8% of OC patients. Other hormonal factors did not differ between the two groups. Conclusions: The carriers of the three Ashkenazi founder mutations should be considered at the same risk for BC and for OC and treatment options should be the same. Mutation carriers diagnosed with BC before the age of 35 are at a very high risk for developing second breast cancer. Most ovarian cancers in carriers were diagnosed after age 45, and prophylactic oophorectomy should be postponed to the age of 45. Oral contraceptives might elevate the risk of BC in mutation carriers.

OBJECTIVE von Hippel-Lindau (VHL) disease and multiple endocrine neoplasia type 2 (MEN2) are auto-somal dominant cancer syndromes. In both conditions, phaeochromocytoma is a prominent feature. It has recently been suggested that phaeochromocytoma can be the presenting and sole clinical manifestation of these multi-organ syndromes. The aim of this study was to ascertain the incidence of VHL and MEN2 among patients with sporadic phaeochromocytoma by mutational analysis. PATIENTS Twenty-seven unrelated patients with biochemically and/or anatomically proven sporadic phaeochromocytoma were evaluated. DESIGN AND MEASUREMENTS Constitutional DNA obtained from the patients was analysed by single stranded conformational analysis (SSCP) for mutations within the VHL gene coding sequence and by denaturing gradient gel electrophoresis (DGGE) for predominant mutations in exons 10, 11 and 16 of the RET proto-oncogene. The incidence of patients positive for either VHL or RET germline mutations was assessed. RESULTS Twenty-six of 27 patients had normal SSCP patterns in all three VHL gene exon segments and only one patient, with an atypical clinical presentation, had an aberrant pattern in exon 3 which upon DNA sequencing was shown to harbor a G to A transversion mutation at nucleotide 695. All patients had normal RET exon 10, 11 and 16 DGGE migration patterns. CONCLUSION Most, if not all, patients with typical unilateral sporadic phaeochromocytoma do not have von Hippel-Lindau disease or MEN2. Thus, clinical and/or molecular investigation for von Hippel-Lindau disease and MEN2 in this patient population does not appear to be indicated.

We have tested 144 unrelated Jewish patients suffering from the classical form of cystic fibrosis. The patients were screened for a panel of 12 mutations including the six Ashkenazi founder mutations (DeltaF508, W1282X, N1303K, G542X, 3849 + 10 kb C-->T, 1717-1G > A) and six mutations that were found in non-Ashkenazi Jewish patients (S549R (T-->G), G85E, 405 + 1G-->A, W1089X, Y1092, and D1152H). Patients of Georgian origin were tested also for the Q359K/T360K mutation. In addition, all the patients were tested for the IVS-8 variant (9T/7T/5T). Of all the cystic fibrosis (CF)-bearing chromosomes, 94% (264/281) were accounted for by one of the known mutations, and none of the patients had the 5T allele of the IVS-8 variant. Single strand conformation polymorphism (SSCP) analysis of the coding sequence of the CFTR gene followed by sequencing showed eight mutations on ten CF chromosomes, leaving seven chromosomes (2.5%) with unknown mutations. We identified three mutations in two or more CF chromosomes, 2571 + 1insT in Jews from Iraq, 3121-1G > A in patients from Kurdistan and I1234V in Yemenite Jewish patients. The other five mutations appeared on a single allele and are considered "private mutations." In this study we have identified 99% of CF alleles in Ashkenazi Jewish patients, 91% in Jews of North African origin and 75% in Jewish patients from Iraq. The significance of these findings to the population screening in Israel is discussed.

Lipoid proteinosis (LP) is a systemic autosomal recessive disorder caused by mutations in the ECM1 (extracellular matrix protein 1) gene1 and is occasionally associated with cognitive impairment, headache, and temporal lobe epilepsy.2 A 37-year-old woman with characteristic cutaneous lesions (figure 1), bilateral cataracts, and lens subluxation was evaluated for diffuse cognitive impairment and headache. Neuroimaging revealed bilateral amygdaloid calcifications typical for LP (figure 2). Sequencing the ECM1 gene identified homozygosity for a splice-site mutation, c.195 + 1G > C in intron 1. This case illustrates the various clinical manifestations of LP (none suggestive of amygdala involvement), which should be considered in the differential diagnosis of cerebral calcifications.

The estimated incidence of radiation-associated sarcoma (RAS) is 0.03–0.2 % in 5 years post treatment. Most cancer predisposing genes are involved in DNA repair; therefore, elevated RAS risk in these patients is plausible. Cases of angiosarcoma post breast cancer treatment were reported in BRCA1 and BRCA2 carriers. We report the genetic evaluation of seven cases with suspected RAS from patients counseled in our cancer-genetic clinic. Of 2,885 breast cancer patient, 470 were BRCA1 or two mutation carriers and three were p53 mutation carriers. Of them seven developed sarcoma in the field of irradiation; five in the chest wall and two in other sites. Genetic evaluation revealed BRCA1 mutation in two, BRCA2 mutation in additional patient and a carrier of p53 mutation. The estimation of risk for RAS in patients with genetic predisposition is limited due to the rarity of this event, and the bias in referral to the clinic toward younger age. With these limitations the rate of RAS is 0.43 % (2/470, 95 % CI −0.17 to 1.02, SE = 0.3) in this group in a median follow-up of 8.2 years (range 1 month to 51 years). If we assume irradiation for the breast in 80 % of the patients than rate of RAS in group is proximately 0.53 % (2/376, 95 % CI −0.21 to 1.26, SE = 0.37). A BRCA1 carrier which had sarcoma after irradiation to head and neck carcinoma was not included in these analyses. In conclusion, we found a high frequency of BRCA1/2 mutation among our patients diagnosed with RAS. However, we estimated approximately twofold increase in the risk of RAS in BRCA1/2 carriers which was not significant compared to reports in general population. Therefore, RAS is a rare event in BRCA carriers as in the general population, and should not be considered in the decision regarding irradiation treatment in this population.

Machado-Joseph disease (MJD) is an autosomal dominant neurodegenerative disorder associated with the expansion of a CAG trinucleotide repeat in the MJD1 gene located on 14q32.1. We confirmed that the CAG expansion caused MJD in a Yemenite Jewish family and demonstrated that most of the clinical variation among members of this family was due to the genotype of the affected individuals. Six patients who presented with an early onset (25 years) and severe disorder were found to be homozygous for the CAG expansion. Among 5 heterozygotes for the CAG expansion older than 40 years, one had neurological symptoms from the age of 45, while the others were asymptomatic. In one of the heterozygotes, no neurological symptoms were present when last examined at the age of 66. Homozygosity for the MJD1 mutation was the main cause of variability in this large family, however, other factors clearly played a role in the expression of the gene. We could demonstrate that homozygote sibs with similar expansion in both alleles had significant differences in disease severity. Gender did not affect the clinical expression in this family.

Two de novo abnormal derivatives of chromosome 15, inv dup(15) and dup(15q) were found in a girl with developmental delay and mild dysmorphological signs. Fluorescence in situ hybridization, using DNA probes of the Prader-Willi/Angelman syndromes (PWS/AS) critical region and chromosome-15-specific alpha-satellite, combined with molecular analysis using dinucleotide repeat polymorphisms within the PWS/AS region and the parent-of-origin specific methylation sites at the locus D15S63, shed light on how the abnormal karyotype was formed. We suggest that a translocation between the two homologues of maternal chromosomes 15 resulted in the formation of dup(15q) and two reciprocal products: an acentric fragment of 15q that was lost and a centric fragment that underwent U-type reunion to form inv dup(15).

Myotonic dystrophy (DM) is an autosomal dominant, multisystem disorder and the most common adult form of muscular dystrophy. The age of onset and degree of severity of DM is highly variable. The biochemical defect in DM is unknown. DM was the first autosomal disorder to be localised by genetic linkage to protein markers (Lu, Se, C3), and assigned to chromosome 19. Linkage studies in DM families using RFLPs as polymorphic markers refined the mapping position to 19q13.1-13.2 distal to the BCL3, apoCII, CKM and ERCCI genes. Based on the linkage data, healthy individuals from DM families request a pre-symptomatic test. The information is of use in planning their family, if at high risk they can choose to have prenatal diagnosis. We have studied ten unrelated DM families by linkage analysis. The DNA probes to detect the various RFLPS were either from the vicinity of BCL3, ApoCII, CKMM and ECCRI genes or anonymous DNA probes. Linkage analysis in the DM families enabled us to determine the carrier status of healthy individuals and to perform prenatal diagnosis at a confidence of > 99%. In two families the DM diagnosis was in doubt and we did not include them in the combined analysis. Linkage disequilibrium was noted with two RFLPs pDIO/Pst1 and p37.1/BamH1. Both DNA probes were isolated by Shaw and his group in Cardiff. In six out of eight families, the DM chromosome was associated with allele 3 of pDIO/Pst1 and allele 1 of p37.1/BamH1.(ABSTRACT TRUNCATED AT 250 WORDS)

Forty-two fetuses with non-homologous Robertsonian translocations were analyzed for uniparental disomy (UPD). One fetus with a de novo translocation t(13q;14q) had maternal isodisomy of chromosome 14. In a summary of the published data (including the present study), 315 cases were analyzed for UPD after prenatal diagnosis of balanced Robertsonian translocations, of these two fetuses had UPD, giving a risk estimate of 0.65% (CI 0.2–2.3). This risk justifies the recommendation of UPD analysis in fetuses diagnosed prenatally with Robertsonian translocations, with the emphasis on the chromosomes known to contain imprinted genes, such as 14 and 15. We also discuss the possibility of UPD in offspring of Robertsonian translocation carriers with normal karyotype. Based on the risk for UPD in fetuses with Robertsonian translocation we suggest to test these fetuses for UPD and to do so on amniocytes rather than chorionic villi when the risk for unbalanced karyotype is ∼1%, comparable to the risk for UPD. Copyright © 2002 John Wiley & Sons, Ltd.

D15S63 is one of the loci, on chromosome 15q11-q13, that exhibit parent-of-origin dependent methylation and that is commonly used in the diagnosis of Prader-Willi or Angelman syndromes (PWS/AS). A 28-kb deletion spanning the D15S63 locus was identified in five unrelated patients; in each of them the deletion was inherited from a normal parent. Three of the five families segregating the deletion were reported to be of Jewish Ashkenazi ancestry, and in the other two families the ancestral origin was unknown. To determine whether the 28-kb deletion is a benign variant, we screened for the deletion in 137 unselected Ashkenazi individuals and in 268 patients who were referred for molecular diagnosis of PWS/AS, of whom 89 were Ashkenazi and 47 were of mixed origin (Ashkenazi and non-Ashkenazi Jews). In the control group, three individuals were carriers of the deletion; among the patients, three were carriers, all of whom were Ashkenazi Jews. There was no significant difference between the control group and the Ashkenazi patients, indicating that the deletion is not a cause of PWS- and AS-like syndromes. The frequency of the 28-kb deletion in the Ashkenazi population was 1/75. Since methylation analysis at the D15S63 locus may lead to misdiagnosis, we suggest the use of SNRPN, either in a PCR-based assay or as a probe in Southern hybridization, as the method of choice in the diagnosis of PWS/AS.

Hydrocephalus is a clinically and genetically heterogeneous condition. Individuals with posterior fossa abnormalities have an increased risk of developing hydrocephalus. The Dandy-Walker malformation, Dandy-Walker variant, and mega-cisterna magna (MCM) seem to represent a continuum of developmental anomalies of the posterior fossa. Here we describe the natural clinical history and the radiological features of a family with autosomal or X-linked dominant inheritance of MCM and hydrocephalus of variable severity. The affected family members demonstrate similar structural brain abnormalities including midline cyst, colpocephaly, MCM with a large posterior fossa and minimal vermian hypoplasia. The cognitive development of the affected individuals is normal. L1CAM and FOXC1 gene involvement in the pathogenesis of the disease in this family was excluded. The rare possibility of autosomal dominant or X-linked dominant inheritance and variable penetrance and expressivity must always be considered in genetic counseling of families with hereditary hydrocephalus.

Autosomal recessive nonsyndromic sensorineural hearing loss (ARNSHL) in Ashkenazi Jews, is mainly caused by mutations in the GJB2 and GJB6 genes. Here we describe a novel homozygous mutation of the LOXHD1 gene resulting in a premature stop codon (R1572X) in nine patients of Ashkenazi Jewish origin who had severe-profound congenital non-progressive ARNSHL and benefited from cochlear implants. Upon screening for the mutation among 719 anonymous Ashkenazi-Jews we detected four carriers, indicating a carrier rate of 1:180 Ashkenazi Jews. This is the second reported mutation in the LOXHD1 gene, and its homozygous presence in two of 39 Ashkenazi Jewish families with congenital ARNSHL suggest that it could account for some 5% of the familial cases in this community.

Mutations in DNA mismatch repair genes underlie lynch syndrome (HNPCC). Lynch syndrome resulting from mutations in MSH6 is considered to be attenuated in comparison to that caused by mutations in MLH1 and MSH2, thus more likely to be under diagnosed. In this study we report of a common mutation in the MSH6 gene in Ashkenazi Jews. Genetic counseling and diagnostic work-up for HNPCC was conducted in families who attended the high risk clinic for inherited cancer. We identified the mutation c.3984_3987dup in the MSH6 gene in 19 members of four unrelated Ashkenazi families. This mutation results in truncation of the transcript and in loss of expression of the MSH6 protein in tumors. Tumor spectrum among carriers included colon, endometrial, gastric, ovarian, urinary, and breast cancer. All but one family qualified for the Bethesda guidelines and none fulfilled the Amsterdam Criteria. Members of one family also co-inherited the c.6174delT mutation in the BRCA2 gene. The c.3984_3987dup in the MSH6 gene is a mutation leading to HNPCC among Ashkenazi Jews. This is most probably a founder mutation. In contrast to the c.1906G>C founder mutation in the MSH2 gene, tumors tend to occur later in life, and none of the families qualified for the Amsterdam criteria. c.3984_3987dup is responsible for 1/6 of the mutations identified among Ashkenazi HNPCC families in our cohort. Both mutations: c.3984_3987dup and c.1906G>C account for 61% of HNPCC Ashkenazi families in this cohort. These findings are of great importance for counseling, diagnosis, management and surveillance for Ashkenazi families with Lynch syndrome.

Hereditary non-polyposis colorectal cancer is a cancer predisposition syndrome known to be caused by heterozygous germline mutations in DNA mismatch repair genes (MMR) most commonly hMLH1, hMSH2, hMSH6. Heterozygous mutations in one of these genes confer an increased risk, mainly for colon and endometrial cancer. Recently, several publications identified that biallelic mutations in the MMR genes are associated with a more severe phenotype, including childhood malignancies and signs of neurofibromatosis type I (NF1). We report on a non-consanguineous Ashkenazi Jewish family with two affected siblings with features of NF1, colon cancer and astrocytoma at age 13 and 14. Their mother developed endometrial cancer at age 54. Their father had leukoplakia of the vocal cords with a family history of pancreatic cancer. Molecular and pathology studies were done on the tumor tissue and on genomic DNA of family members. Tumor testing demonstrated a high degree of microsatellite instability (MSI analysis), expression of MLH1 and absence of expression of both MSH2 and MSH6 proteins. A biallelic c.1906G > C (p.A636P) mutation in the hMSH2 gene was detected in the blood of one affected child. Parental genetic testing showed that each parent was heterozygote for the mutation. The c.1906G > C mutation is a founder mutation in the Ashkenazi Jewish population. To our knowledge this is the first report of homozygosity for this founder mutation.

Hereditary spastic paraplegias (HSP) are neurodegenerative diseases mainly characterized by lower limb spasticity associated, in complicated forms, with additional neurological signs. We have analysed a large series of index patients (n = 76) with this condition, either from families with an autosomal recessive inheritance (n = 43) or isolated patients (n = 33), for mutations in the recently identified SPG11 gene. We found 22 truncating mutations, including the first four splice-site mutations, segregating in seven isolated cases and 13 families. Nineteen mutations were novel. Two recurrent mutations were found in Portuguese and North-African patients indicating founder effects in these populations. The mutation frequency varied according to the phenotype, from 41%, in HSP patients presenting with a thin corpus callosum (TCC) visualized by MRI, to 4.5%, in patients with mental impairment without a TCC. Disease onset occurred during the first to the third decade mainly by problems with gait and/or mental retardation. After a mean disease duration of 14.9 +/- 6.6 years, the phenotype of 38 SPG11 patients was severe with 53% of patients wheelchair bound or bedridden. In addition to mental retardation, 80% of the patients showed cognitive decline with executive dysfunction. Interestingly, the phenotype also frequently included lower motor neuron degeneration (81%) with wasting (53%). Slight ocular cerebellar signs were also noted in patients with long disease durations. In addition to a TCC (95%), brain MRI revealed white matter alterations (69%) and cortical atrophy (81%), which worsened with disease duration. In conclusion, our study reveals the high frequency of SPG11 mutations in patients with HSP, a TCC and cognitive impairment, including in isolated patients, and extends the associated phenotype.

Hereditary non-polyposis colon cancer is caused by mutations in DNA mismatch repair genes. The mutation spectrum in the Israeli population is poorly documented except for the c.1906G>C Ashkenazi founder mutation in the hMSH2 gene. To report our experience in HNPCC screening, the mutations detected and the clinical features among a cohort of Israeli patients. Diagnostic work-up was done in a multi-step process guided by clinical and ethnic information. Tumors of suspected patients were tested for microsatellite instability and immunohistochemistry. Based on tumor analyses, we proceeded to mutation screening by DHPLC followed by sequence analysis and multiplex ligase dependent probe amplification. Ashkenazi Jews were first tested for the c.1906G>C founder mutation. Of the 240 families, 24, including Arabs and Jews from different ethnic origins, were tested positive. All tumors that lost expression of mismatch repair proteins also showed microsatellite instability. There was evidence for involvement of hMSH2 (15) hMLH1 (6) and hMSH6 (3) genes. Mutations were identified in 17/24 (71%) patients: 6 Ashkenazi families harbored the c.1906G>C mutation. Eleven other mutations (2 nonsense, 3 splice site and 6 small deletions) were detected. Three of the mutations are novel. No gross deletions or insertions were detected. This is the first report that characterizes the profile of HNPCC in a cohort of patients in Israel. Tumor testing indicated that the 3 main MMR genes are involved, and that mutation spectrum is broad.

Hereditary spastic paraplegia (HSP) type 15 is an autosomal recessive (AR) form of complicated HSP mainly characterized by slowly progressive spastic paraplegia, mental retardation, intellectual deterioration, maculopathy, distal amyotrophy, and mild cerebellar signs that has been associated with the Kjellin syndrome. The locus for this form of HSP, designated SPG15, was mapped to an interval of 19 cM on chromosome 14q22-q24 in two Irish families. We performed a clinical-genetic study of this form of HSP on 147 individuals (64 of whom were affected) from 20 families with AR-HSP. A genome-wide scan was performed in three large consanguineous families of Arab origin after exclusion of linkage to several known loci for AR-HSP (SPG5, SPG7, SPG21, SPG24, SPG28, and SPG30). The 17 other AR-HSP families were tested for linkage to the SPG15 locus. Only the three large consanguineous families showed evidence of linkage to the SPG15 locus (2.4 > Z (max) > 4.3). Recombinations in these families reduced the candidate region from approximately 16 to approximately 5 Mbases. Among the approximately 50 genes assigned to this locus, two were good candidates by their functions (GPHN and SLC8A3), but their coding exons and untranslated regions (UTRs) were excluded by direct sequencing. Patients had spastic paraplegia associated with cognitive impairment, mild cerebellar signs, and axonal neuropathy, as well as a thin corpus callosum in one family. The ages at onset ranged from 10 to 19 years. Our study highlights the phenotypic heterogeneity of SPG15 in which mental retardation or cognitive deterioration, but not all other signs of Kjellin syndrome, are associated with HSP and significantly reduces the SPG15 locus.

Hereditary non-polyposis colorectal cancer (HNPCC) is an autosomal dominant cancer predisposition syndrome associated with a high risk for colorectal cancer (up to 80%), endometrial cancer (up to 60%), and increased risk for other malignancies, mostly ovarian and urinary system tumors. HNPCC is caused by a germline mutation in one of the mismatch repair (MMR) genes, mainly hMLH1, hMSH2 and hMSH6. The tumors present with microsatellite instability (MSI) associated with loss of heterozygosity of the affected gene, and with loss of expression of the gene product. Diagnosis of HNPCC involves tumor testing for MSI, immunohistochemistry staining and germ line mutation analysis of the suspected gene. Proper genetic counseling is based on the synthesis of the clinical, pathological and molecular data. Directed surveillance shows significant reduction in colon cancer incidence, cancer mortality and overall mortality among HNPCC patients.To establish a multidisciplinary service for patients suspected of having HNPCC.We have established a service which is based on tight collaboration between clinical departments and laboratories. The clinical work-up was conducted by a special oncogenetic clinic and the laboratory service consisted of tissue testing for MSI and immunohistochemistry, denaturing high performance liquid chromatography (DHPLC) for suspected genes, and mutation testing.The efficiency of detection of patients with HNPCC was high, completed in a multistep process. In the first year of our collaborative work, we have provided genetic counseling to over 100 families and performed suitable tests for 46 families. Among them we have identified more than 16 families with HNPCC; 4 showed absence of hMLH1, 1 showed absence of hMSH6, and 11 showed absence of hMSH2. All tumors that showed MSI also showed absence of either one of the three MMR proteins. We present the clinical, pathological and molecular features of our patients and discuss the implication of this data on future recommendations.

Background Telangiectases are abnormal dilatations of end vessels in the subpapillary plexus of the papillary dermis. Hereditary benign telangiectasia (HBT) (OMIM 187260) is a genetic skin disorder, characterized by multiple cutaneous telangiectases appearing in the first years of life in various locations. Several familial cases of HBT have been described displaying autosomal dominant inheritance. In some of the described pedigrees, telangiectases are limited to sun-exposed areas, whereas in others lesions are randomly distributed over the body. The disorder has been previously mapped to a 7Mb interval on chromosome 5q14 ( CMC1 locus) in an Italian pedigree with randomly distributed telangiectases. Objectives A large pedigree of HBT with photodistributed lesions is described. We sought to determine whether photodistributed HBT is linked to the CMC1 locus. Methods In all, 35 family members were examined. DNA was extracted from blood and saliva samples. Linkage analysis to CMC1 locus on chromosome 5q14 was screened by using 3 polymorphic markers. Results In all, 23 family members were found to have variable numbers of cutaneous radiating macular telangiectases, measuring 1 to 3 cm and distributed over the face, back of the hands, and forearms. HBT in this family is inherited in an autosomal dominant pattern with incomplete penetrance. Linkage to the CMC1 locus was excluded. Limitation Only one family, although very large, was studied in this project. Conclusions Clinical and genetic heterogeneity is evident in HBT. Photodistributed HBT is not related pathogenically to capillary malformations or to randomly distributed hereditary telangiectases and should be recognized as a separate entity.

Background Hereditary spastic paraplegia (HSP) with thin corpus callosum (TCC) is an autosomal recessive form of complicated HSP mainly characterized by slowly progressive spastic paraparesis and mental deterioration beginning in the second decade of life. The locus for HSP-TCC, designated SPG11 , was mapped to chromosome 15q13-15 in some of the affected families from Japan, Europe, and North America, spanning an interval of 17.5 megabases (Mb). Objective To perform a clinical and genetic study of HSP-TCC. Design and Setting Case series; multi-institutional study. Patients Seven patients with HSP-TCC who belong to 3 consanguineous families of Arab origin residing in Israel. Results The 7 patients manifested a relatively similar combination of adolescence-onset cognitive decline and spastic paraparesis with TCC on brain magnetic resonance imaging. After excluding the SPG7 locus, we tested the 3 families for linkage to the SPG11 , SPG21/MAST , and ACCPN loci associated with autosomal recessive disorders with TCC. Two families showed evidence for linkage to SPG11 (Z max = 5.55) and reduced the candidate region to 13 Mb. Conclusions Our findings in HSP-TCC further confirm its worldwide distribution and genetic heterogeneity, and they significantly reduce the candidate SPG11 interval.

Mutations in the gene NPHS2 encoding podocin are responsible for a recessive form of steroid-resistant nephrotic syndrome (SRNS). The common phenotype is of massive proteinuria in early childhood that tends to progress to end-stage renal failure. Extrarenal manifestations have not been described. Twenty-two children with SRNS from six unrelated Arab families were found to be homozygous for the R138X mutation in NPHS2. Eighteen patients underwent cardiac evaluation at diagnosis of SRNS while they had normal BP and preserved renal function. Cardiac anomalies were detected in 16 (89%) children: Left ventricular hypertrophy in eight, pulmonary stenosis in six, discrete subaortic stenosis in two, and Ebstein anomaly and ventricular septal defect in one each. The remaining four affected individuals were assessed only once they had end-stage renal failure. They had severe left ventricular hypertrophy and experienced repeated episodes of heart failure. Two control groups were equally evaluated. The first consisted of 37 siblings without nephrotic syndrome, of whom only one carrier had a cardiac defect (P < 0.001). None of the second group, which included 22 children with persistent nephrotic syndrome as a result of other causes, had a cardiac anomaly (P < 0.001). Cardiac disorders in homozygotes for mutations in NPHS2 cannot be attributed to an association by chance or to a state of persistent nephrotic syndrome. Because human podocin mRNA is expressed in fetal heart, it is speculated that it may have a role in normal cardiac development. Cardiac evaluation is recommended at the time of diagnosis of SRNS due to mutations in podocin.