Search

Lynch syndrome (LS) and constitutional mismatch repair deficiency (CMMRD) are distinct cancer syndromes caused, respectively, by mono- and bi-allelic germline mismatch repair (MMR) variants. LS predisposes to mainly gastrointestinal and genitourinary cancers in adulthood. CMMRD predisposes to brain, haematological, and LS-spectrum cancers from childhood. Two suspected LS patients with first cancer diagnosis aged 27 or 38 years were found to be homozygous for an MMR (likely) pathogenic variant, MSH6 c.3226C>T (p.(Arg1076Cys)), or variant of uncertain significance (VUS), MLH1 c.306G>A (p.(Glu102=)). MLH1 c.306G>A was shown to cause leaky exon 3 skipping. The apparent genotype-phenotype conflict was resolved by detection of constitutional microsatellite instability in both patients, a hallmark feature of CMMRD. A hypomorphic effect of these and other variants found in additional late onset CMMRD cases, identified by literature review, likely explains a LS-like phenotype. CMMRD testing in carriers of compound heterozygous or homozygous MMR VUS may find similar cases and novel hypomorphic variants. Individualised management of mono- and bi-allelic carriers of hypomorphic MMR variants is needed until we better characterise the associated phenotypes. [ABSTRACT FROM AUTHOR]

A dose non-inferiority study comparing 100 mg, 300 mg and 600 mg of aspirin for cancer prevention among Lynch Syndrome carriers is underway (Colorectal Adenoma/Carcinoma Prevention Programme trial 3, CaPP3). To guide implementation of the findings, we investigated general practitioner (GP) attitudes towards aspirin prescribing for Lynch Syndrome carriers. We surveyed 1007 UK GPs (9.6% response rate). Using a within-subjects design, GPs read a statement on harms and benefits of aspirin and indicated their willingness to prescribe aspirin at three doses (100 mg, 300 mg, 600 mg). Approximately two-thirds (70.8%) of GPs had heard of Lynch Syndrome or its associated names, and among those 46.7% were aware of the cancer preventive effects of aspirin among carriers. Two-thirds (68.1%) of GPs reported feeling comfortable discussing harms and benefits of aspirin with a Lynch Syndrome patient. Willingness to prescribe was 91.3% at 100 mg, and declined to 81.8% at 300 mg and 62.3% at 600 mg ( p < 0.001). In multivariable analyses, willingness to prescribe (600 mg) was higher among GPs ≥50 years (OR 1.46, 95% CI 1.03-2.07), more experienced GPs (OR 1.50, 95% CI 1.10-2.04), GPs who were aware of the cancer preventive effects of aspirin (OR 1.58, 95% CI 1.20-2.09), and those who reported seeing a Lynch Syndrome patient in practice (OR 1.44, 95% CI 1.01-2.05, p = 0.045). GPs report limited awareness of Lynch Syndrome and the preventive effects of aspirin among carriers. To ensure the optimal dose identified in the CaPP3 trial is readily available to patients, prescribing guidance and strategies to educate GPs should be developed. [ABSTRACT FROM AUTHOR]

CAPP1 tested aspirin 600 mg/day and/or resistant starch 30 g/day in 200 adolescent FAP carriers. Aspirin treatment resulted in a non-significant reduction in polyp number and a significant reduction in polyp size among patients treated with aspirin for more than 1 year. CAPP2 RCT used the same interventions in 937 Lynch syndrome patients, the first RCT to have cancer prevention as the primary endpoint. Aspirin did not reduce the risk of colorectal neoplasia in a mean treatment period of 29 months but double blind post intervention follow-up has revealed 48 participants developed 53 CRCs. Per protocol analysis showed 63 % fewer colon cancers with aspirin ( p = 0.008) apparent from 4 years, with a similar effect on other LS cancers. Resistant starch was not beneficial at long term followup. CAPP3 will involve a double blind dose non-inferiority trial comparing 100, 300 or 600 mg daily in 3,000 gene carriers. We can now recommend aspirin in people at high risk of colorectal cancer. [ABSTRACT FROM AUTHOR]

The original online version of this article was revised: "Letter to the Editor has been included in article title" In April 2019, Familial Cancer published an article "Recent advances in Lynch Syndrome" by Biller, Syngal and Yurgelun [[1]]. 6450737 2 Engel C, Vasen HF, Seppala T. No difference in colorectal cancer incidence or stage at detection by colonoscopy among 3 countries with different Lynch syndrome surveillance policies. 2020; 8: 6. 10.1186/s13053-020-0138-0 7 Seppälä TT, Dominguez-Valentin M, Sampson JR, Møller P. Prospective observational data informs understanding and future management of Lynch syndrome: insights from the Prospective Lynch Syndrome Database (PLSD). [Extracted from the article]

Neuroferritinopathy is an autosomal dominant progressive movement disorder which occurs due to mutations in the ferritin light chain gene ( FTL1). It presents in mid-adult life and is the only autosomal dominant disease in a group of conditions termed neurodegeneration with brain iron accumulation (NBIA). We performed brain MRI scans on 12 asymptomatic descendants of known mutation carriers. All three harbouring the pathogenic c.460InsA mutation showed iron deposition; these findings show pathological iron accumulation begins in early childhood which is of major importance in understanding and developing treatment for NBIA. [ABSTRACT FROM AUTHOR]

Endometrial cancer is frequent in MMR-mutation carriers. Estimates of annual incidence rates have, however, been based on retrospective studies. The purpose of our study was to prospectively assess the incidence rates of endometrial cancer in women either having a mutation in one of the four MMR genes MLH1, MSH2, MSH6 or PMS2 (Mut+) or belonging to families meeting the revised Amsterdam criteria in which no MMR mutation was detected (Ams+). Eight out of 80 Mut+ (10%) contracted invasive endometrial cancer compared to 1/171 (0.6%) of the Ams+ ( P = 0.0006). The annual incidence rate after first control was 2.5% in Mut+ and 0.2% in Ams+. Two of the 8 Mut+ women (25%) had synchronous gynaecological tumours. The numbers included did not allow for firm conclusions, but the results are in keeping with the notion that the inherited colon-endometrial cancer syndrome may be restricted to carriers of MMR mutations. [ABSTRACT FROM AUTHOR]

The aims of this study were (1) to determine trends in total prevalence and live birth prevalence of Down syndrome, (2) to analyse trends in factors likely to influence this prevalence and (3) to determine 1-year survival in Down syndrome. A retrospective review was made of prospectively collected data on all cases of Down syndrome within a malformation registry born in 1985–2004. Down syndrome affected 1188 pregnancies among 690 215 live births (1.72 per 1000 total births). The proportion increased over 20 years from 1.3 to 2.5 per 1000 total births (P<0.0001). There were 389 terminations for Down syndrome and 51 stillbirths. There were 748 live births with Down syndrome (1.08 per 1000 live births). The live birth prevalence declined in 1985–1994 and increased in 1995–2004 with no overall change. Total live births in the population declined by 20% over 20 years. Mothers delivering at 35 years of age or above increased from 6 to 15%. The uptake of maternal serum screening increased from zero in 1987 to 35% in 1993 but then plateaued. One-year survival of live births with Down syndrome increased, especially in babies with cardiovascular malformations, reaching almost 100%. The prevalence of pregnancies affected by Down syndrome has increased significantly, but there has been no overall change in live birth prevalence. Increasing maternal age and improved survival of children with Down syndrome have offset the effects of prenatal diagnosis followed by the termination of pregnancy and declining general birth rate.European Journal of Human Genetics (2008) 16, 1336–1340; doi:10.1038/ejhg.2008.122; published online 2 July 2008 [ABSTRACT FROM AUTHOR]

Cornelia de Lange syndrome (CdLS) is a rare developmental malformation syndrome characterised by mental handicap, growth retardation, distinctive facial features and limb reduction defects. The vast majority of CdLS cases are sporadic. We carried out a high density bacterial artificial chromosome (BAC) microarray comparative genome hybridisation screen but no evidence was found for a consistent pattern of microdeletion/microduplication. As an alternative, we focused on identifying chromosomal regions spanning associated translocation breakpoints. We prioritised the distal 3q region because of the occurrence, in a classical CdLS patient, of a de novo balanced translocation with a breakpoint at 3q26.3 and of reports of phenotypic overlap between cases of mild CdLS and individuals trisomic for the 3q26-q27 region. We show that the 3q26.3 breakpoint severs a previously uncharacterised giant gene, NAALADL2, containing at least 32 exons spanning 1.37 Mb. Northern blot analysis identified up to six different transcripts in the 1–10 kb range with strongest expression in kidney and placenta; embryonic expression was largely confined to duodenal and stomach endoderm, mesonephros, metanephros and pancreas. Transcript analysis identified extensive alternative splicing leading to multiple 5′ and 3′ untranslated regions and variable coding sequences. Multiple protein isoforms were defined by different N-terminal regions (with at least four alternative initiating methionine codons), and by differential protein truncation/use of alternative C-terminal sequences attributable to alternative splicing/polyadenylation. Outside the N-terminal regions, the predicted proteins showed significant homology to N-acetylated alpha-linked acidic dipeptidase and transferrin receptors. Mutation screening of NAALADL2 in a panel of CdLS patient DNA samples failed to identify patient-specific mutations. We discuss the possibility that the 3q26.3 translocation could nevertheless contribute to pathogenesis. [ABSTRACT FROM AUTHOR]

Linkage analysis and haplotype mapping in interspecific mouse crosses (Mus musculus × Mus spretus) identified the gene encoding Aurora2 (Stk6 in mouse and STK15 in human) as a candidate skin tumor susceptibility gene. The Stk6 allele inherited from the susceptible M. musculus parent was overexpressed in normal cells and preferentially amplified in tumor cells from F1 hybrid mice. We identified a common genetic variant in STK15 (resulting in the amino acid substitution F31I) that is preferentially amplified and associated with the degree of aneuploidy in human colon tumors. The Ile31 variant transforms rat1 cells more potently than the more common Phe31 variant. The E2 ubiquitin-conjugating enzyme UBE2N was a preferential binding partner of the 'weak' STK15 Phe31 variant form in yeast two-hybrid screens and in human cells. This interaction results in colocalization of UBE2N with STK15 at the centrosomes during mitosis. These results are consistent with an important role for the Ile31 variant of STK15 in human cancer susceptibility. [ABSTRACT FROM AUTHOR]

Nance-Horan syndrome (NHS) is an X-linked condition characterised by congenital cataracts, dental abnormalities, dysmorphic features, and mental retardation in some cases. Previous studies have mapped the disease gene to a 2 cM interval on Xp22.2 between DXS43 and DXS999. We report additional linkage data resulting from the analysis of eleven independent NHS families. A maximum Iod score of 9.94 (θ=0.00) was obtained at the RS1 locus and a recombination with locus DXS1195 on the teiomeric side was observed in two families, thus refining the location of the gene to an interval of around 1 Mb on Xp22.13. Direct sequencing or SSCP analysis of the coding exons of five genes (SCML1, SCML2, STK9, RS1 and PPEF1), considered as candidate genes on the basis of their location in the critical interval, failed to detect any mutation in 12 unrelated NHS patients, thus making it highly unlikely that these genes are implicated in NHS. [ABSTRACT FROM AUTHOR]

We describe here a previously unknown, dominantly inherited, late-onset basal ganglia disease, variably presenting with extrapyramidal features similar to those of Huntington's disease (HD) or parkinsonism. We mapped the disorder, by linkage analysis, to 19q13.3, which contains the gene for ferritin light polypeptide (FTL). We found an adenine insertion at position 460?461 that is predicted to alter carboxy-terminal residues of the gene product. Brain histochemistry disclosed abnormal aggregates of ferritin and iron. Low serum ferritin levels also characterized patients. Ferritin, the main iron storage protein, is composed of 24 subunits of two types (heavy, H and light, L) which form a soluble, hollow sphere. Brain iron deposition increases normally with age, especially in the basal ganglia, and is a suspected causative factor in several neurodegenerative diseases in which it correlates with visible pathology, possibly by its involvement in toxic free-radical reactions. We found the same mutation in five apparently unrelated subjects with similar extrapyramidal symptoms. An abnormality in ferritin strongly indicates a primary function for iron in the pathogenesis of this new disease, for which we propose the name 'neuroferritinopathy'. [ABSTRACT FROM AUTHOR]

Char syndrome is an autosomal dominant trait characterized by patent ductus arteriosus, facial dysmorphism and hand anomalies. Using a positional candidacy strategy, we mapped TFAP2B, encoding a transcription factor expressed in neural crest cells, to the Char syndrome critical region and identified missense mutations altering conserved residues in two affected families. Mutant TFAP2B proteins dimerized properly in vitro, but showed abnormal binding to TFAP2 target sequence. Dimerization of both mutants with normal TFAP2B adversely affected transactivation, demonstrating a dominant-negative mechanism. Our work shows that TFAP2B has a role in ductal, facial and limb development and suggests that Char syndrome results from derangement of neural-crest-cell derivatives. [ABSTRACT FROM AUTHOR]

Mutation searching was performed in the hMSH2 and hMLH1 genes in 20 Portuguese families representing 124 registered affected individuals. Of the 20, 16 fulfilled the classic 'Amsterdam' criteria for HNPCC, whereas the remaining four families satisfied a modified set of criteria. These criteria required a CRC diagnosed before age 50 years and cancers diagnosed in two other relatives within the HNPCC spectrum. A multi-method approach was performed using the protein truncation test (PTT), single strand conformation polymorphism (SSCP) with two different sets of conditions, heteroduplex analysis (HA) and denaturing gradient gel electrophoresis (DGGE). Putative phenotype-genotype correlations were also explored. Ten different germline mutations were identified. Six of these were found in hMLH1 in seven families and four in hMSH2 in four families. SSCP and DGGE had the highest diagnostic yields with the percentage of variants detected above 67% and together HA and PTT had the lowest. No single technique detected all variants. Trends for the absence of extracolonic manifestations were observed in families carrying hMLH1 germline mutations (four of seven in hMLH1 vs one of four in hMSH2). Most of the families with rectal cancer were associated with hMLH1 (six of seven in hMLH1 vs two of four in hMSH2). A multi-technique approach is necessary to identify a high percentage of germline mutations. Seven novel mutations were found in this Portuguese population. [ABSTRACT FROM AUTHOR]

Partial absence of the sacrum is a rare congenital defect which also occurs as an autosomal dominant trait; association with anterior meningocoele, presacral teratoma and anorectal abnormalities constitutes the Currarino triad (MIM 176450). Malformation at the caudal end of the developing notochord at approximately Carnegie stage 7 (16 post-ovulatory days), which results in aberrant secondary neurulation, can explain the observed pattern of anomalies. We previously reported linkage to 7q36 markers in two dominantly inherited sacral agenesis families. We now present data refining the initial subchromosomal localization in several additional hereditary sacral agenesis (HSA) families. We excluded several candidate genes before identifying patient-specific mutations in a homeobox gene, HLXB9, which was previously reported to map to 1q41-q42.1 and to be expressed in lymphoid and pancreatic tissues. [ABSTRACT FROM AUTHOR]

This study reviews the spectrum of congenital heart disease and associated anomalies in 59 patients with the CHARGE association. We have analyzed our clinical experience in managing the cardiovascular anomalies and have reviewed outcome and risk factors for mortality. This study also highlights problems of cardiac management in children born with multiple system involvement. Twenty patients have died; actuarial survival was 78% at 1 year and 60% at 10 years. In only four of the nonsurvivors could their demise be ascribed to their underlying congenital heart disease. We found the outlook for survival was poor if more than one of the following three features were present; cyanotic cardiac lesions, bilateral posterior choanal atresia, or tracheoesophageal fistula. However, mortality was largely due not to the structural heart or choanae abnormalities, but instead reflected the underlying pharyngeal and laryngeal incoordination which resulted in aspiration of secretions. Furthermore, outcome is likely to be improved if collaboration between specialist surgical teams allows necessary procedures to be performed using the minimum of anesthetics. Examination of both the short-and long-term management of these children has stressed the importance of a multidisciplinary approach to their care. The pattern of cardiac defects was not random; lesions within the Fallot spectrum accounted for 33% of their congenital heart disease. Atrioventricular septal defects were also overrepresented. Not all cardiovascular defects could be explained by hypothesizing a neural crest etiology. [ABSTRACT FROM AUTHOR]

A two-year-old child who had had palliative surgery as a neonate for an absent right atrioventricular connection and double-inlet ventricle was shown to be developmentally retarded. Trisomy for the short arm of chromosome 8 was demonstrated, resulting from a familial 8:13 translocation, with a high risk of recurrence. Although the specific features of this case are unique, it illustrates the importance of chromosome analysis in any dysmorphic infant whose heart defect places prolonged survival in doubt. [ABSTRACT FROM AUTHOR]

DiGeorge syndrome in humans is charaterized by immunodeficiency, heart defects, mental retardation and facial dysmorphism; cytogenetic analysis has shown that deletions at 22q11 occur in approximately 25% of cases. To generate DNA markers from this region, we have microdissected and microcloned band q11 of human Chromosome (Chr) 22. Nineteen thousand clones were obtained from material dissected from 20 chromosome fragments. Seventeen of 61 clones analyzed (28%) were repetitive, 27 (44%) gave no signal, and 17 (28%) detected single copy sequences of which ten mapped to Chr 22. Two of these were found to be deleted in patients with DiGeorge syndrome and either monosomy for 22q11-pter or visible interstitial deletions of 22q11. These two markers are also hemizygous in patients with no visible chromosomal abnormality, demonstrating that submicroscopic deletions are common in DiGeorge syndrome patients. [ABSTRACT FROM AUTHOR]

A correction to this paper has been published: https://doi.org/10.1007/s10689-021-00246-0 [ABSTRACT FROM AUTHOR]

17q11 microdeletions that encompass NF1 cause 5%–10% of cases of neurofibromatosis type 1, and individuals with microdeletions are typically taller than individuals with intragenic NF1 mutations, suggesting that deletion of a neighboring gene might promote human growth. We identified mutations in RNF135, which is within the NF1 microdeletion region, in six families characterized by overgrowth, learning disability, dysmorphic features and variable additional features. These data identify RNF135 as causative of a new overgrowth syndrome and demonstrate that RNF135 haploinsufficiency contributes to the phenotype of NF1 microdeletion cases. [ABSTRACT FROM AUTHOR]

Inherited mutations in the gene BRCA2 predispose carriers to early onset breast cancer, but such mutations account for fewer than 2% of all cases in East Anglia. It is likely that low penetrance alleles explain the greater part of inherited susceptibility to breast cancer; polymorphic variants in strongly predisposing genes, such as BRCA2, are candidates for this role. BRCA2 is thought to be involved in DNA double strand break-repair. Few mice in which Brca2 is truncated survive to birth; of those that do, most are male, smaller than their normal littermates and have high cancer incidence. Here we show that a common human polymorphism (N372H) in exon 10 of BRCA2 confers an increased risk of breast cancer: the HH homozygotes have a 1.31-fold (95% CI, 1.07?1.61) greater risk than the NN group. Moreover, in normal female controls of all ages there is a significant deficiency of homozygotes compared with that expected from Hardy-Weinberg equilibrium, whereas in males there is an excess of homozygotes: the HH group has an estimated fitness of 0.82 in females and 1.38 in males. Therefore, this variant of BRCA2 appears also to affect fetal survival in a sex-dependent manner. [ABSTRACT FROM AUTHOR]

The article presents the authors insight on the importance of coordinated international efforts in developing patient phenotype registries and comprehensive mutation databases. They state that coordination in setting databases or registries may promote medical resources for international communications and awareness. Moreover, they mention the role of Human Variome Project (HVP) and the International Rare Diseases Research Consortium (IRDiRC).