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Background Neuronal ceroid lipofuscinoses (NCLs) are a group of neurodegenerative disorders characterized by an accumulation of lipofuscin in the body's tissues. NCLs are associated with variable age of onset and progressive symptoms including seizures, psychomotor decline, and loss of vision. Methods We describe the clinical and molecular characteristics of four Russian patients with NCL (one female and three males, with ages ranging from 4 to 5 years). The clinical features of these patients include cognitive and motor deterioration, seizures, stereotypies, and magnetic resonance imaging signs of brain atrophy. Exome sequencing was performed to identify the genetic variants of patients with NCL. Additionally, we tested 6,396 healthy Russians for NCL alleles. Results We identified five distinct mutations in four NCL‐associated genes of which two mutations are novel. These include a novel homozygous frameshift mutation in the CLN6 gene, a compound heterozygous missense mutation in the KCTD7 gene, and previously known mutations in KCTD7, TPP1, and MFSD8 genes. Furthermore, we estimated the Russian population carrier frequency of pathogenic and likely pathogenic variants in 13 genes associated with different types of NCL. Conclusion Our study expands the spectrum of mutations in lipofuscinosis. This is the first study to describe the molecular basis of NCLs in Russia and has profound and numerous clinical implications for diagnosis, genetic counseling, genotype–phenotype correlations, and prognosis., 5 distinct mutations were identified in 4 NCL‐caused genes, of which two mutations are novel. Also carrier frequency of pathogenic and likely pathogenic variants in 13 genes associated with different types of NCL were estimated in Russian population.

SOD1 mutations are a frequent cause of autosomal dominant familial amyotrophic lateral sclerosis (fALS).1 The D91A SOD1 variant is unique in its association with an atypical form of autosomal recessive fALS in Scandinavia. ALS has also been described in heterozygous D91A carriers,2 but it remains uncertain whether this is pathogenic, given that the D91A carrier state exists in European populations with an allele frequency of 0.007 ([gnomad.broadinstitute.org/][1]), and the observation that ALS does not co-segregate with the heterozygous carrier status in D91A-associated fALS.3 It is generally accepted that dominant SOD1 cases are neuropathologically distinct from sporadic ALS, because of the absence of the TDP-43 proteinopathy found in 97% of all ALS cases, suggesting that different pathogenic mechanisms are involved.4 With the advent of trials of antisense oligonucleotides in SOD1-related ALS it is critical to establish if D91A SOD1 is pathogenic in the heterozygous state, to ensure appropriate recruitment of patients to clinical trials. Here we report a case of corticobulbar ALS in an individual heterozygous for the D91A variant, with autopsy findings of widespread TDP-43 proteinopathy typical of sporadic ALS (figure). [1]: https://gnomad.broadinstitute.org/

PURPOSE To describe the complex, overlapping phenotype expressed in a two generation family harboring pathogenic mutations in the ABCA4 and GPR143 genes. METHODS Clinical evaluation of a two generation family included quantitative autofluorescence imaging (qAF, 488-nm excitation) using a modified confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference to account for varying laser power detector sensitivity, spectral-domain optical coherence tomography, and full-field ERG testing. Complete sequencing of the ABCA4 and GPR143 genes was carried out in each individual. RESULTS Affected individuals presented with bull's eye lesions and qAF levels above the 95% confidence interval for healthy eyes; full-field ERG revealed no generalized rod dysfunction but mild implicit time delays in cone responses. Complete sequencing of the ABCA4 gene revealed two disease-causing mutations, p.L541P and p.G1961E; and mutational phase was confirmed in each unaffected parent. Further examination in the affected patients revealed a peripheral "mud-splattered" pattern of hypopigmented RPE after which sequencing of GPR143 revealed a novel missense variant, p.Y157C. The GPR143 variant segregated from the father who did not exhibit any indications of retinal disease with the exception of an abnormal near-infrared autofluorescence (NIR-AF) signal distribution in the macula. CONCLUSIONS An individual carrying both ABCA4 and GPR143 disease-causing mutations can express a complex, overlapping phenotype associated with both Stargardt disease and X-linked ocular albinism (OA1). The absence of OA1-related disease changes (with the exception of NIR-AF changes associated with melanin distribution) in the father may be indicative of mild expressivity or variable gene penetrance.

Non-classical congenital adrenal hyperplasia (NC-CAH) includes a group of genetic disorders due to a broad class of CYP21A2 variants identifying a disease-causing ‘C’ genotype. The heterozygous carriers of CYP21 mutations are at increased risk of developing clinically evident hyperandrogenism, even though clinical and laboratory characteristics are still underestimated. With the aim of obtaining a more accurate delineation of the phenotype of heterozygous carrier of CAH, we analyzed clinical, biochemical and molecular characteristics in a cohort of Sicilian subjects. Fifty-seven females with biallelic and monoallelic CYP21A2 variants classifying NC-CAH (24) and heterozygous carriers of CAH (33), respectively were selected. Forty-four females age-matched healthy controls were also enrolled and genotyped for CYP21A2. Clinical, hormonal and genetic data were collected. CYP21A2 monoallelic mutations, defining the heterozygous carriers state, were identified in subjects with clinical features including hirsutism, oligomenorrhoea, overweight and a PCO-like phenotype, particularly occurring in the age of adolescence. Consistently, levels of 17OHP and cortisol were found to be significantly different from NC-CAH. Overall, some clinical and laboratory findings including oligomenorrhea and 17OHP/cortisol ratio were observed as independent markers associated with carriers of CAH. Here we report a high prevalence of late-onset signs of polycystic ovary syndrome (PCOS) and hyperandrogenism in heterozygous carriers. The 17OHP/cortisol ratio may be a predictive tool to identify the carriers of CAH, even though specific cut-off values have not yet been identified.

Background: The recessive X-linked disorder hemophilia A (HA) is rarely expressed in female carriers, most of whom express about half of normal factor VIII activity (FVIII:C). Objective: To propose an integrative assessment model for the binary role of the phase between the mutated F8 and the active X-chromosome (Xa) in FVIII:C in HA carriers. Methods: We studied 67 females at risk of severe HA, comprising five symptomatic females (FVIII:C < 1.5 IU dL−1) and 14 controls. A correlation study between FVIII:C (observed vs. expected) and X-chromosome inactivation (XCI) patterns (XIPs; androgen receptor gene [AR] system) in blood leukocyte DNA was performed in carriers, by comparison of a model correlating FVIII:C and XIP with arbitrary models devoid of biological significance, and with FVIII:C levels in non-carriers (mean model) as a proxy from background data dispersion not influenced by XIP. Results: We provide proof-of-concept example from a family presenting with extremely skewed XIPs in which the severe HA phenotype appeared in a heterozygous carrier of a crossover between AR and F8 loci that phased the mutated F8 with the maternally inherited Xa. Furthermore, four cases of severe HA affected women who had a combination of a heterozygous F8 mutation and extremely skewed XIPs in leukocytes or oral mucosa are presented. Correlation analyses between FVIII:C levels and XIPs in carriers (n = 38) but not in non-carriers (n = 20) showed highly significant differences between the proposed correlation model and models without biological significance. The data support a binary influence of XCI, either increasing or decreasing the FVIII:C, subject to the underlying phase set between the F8 mutation and XCI. Conclusions: Our evidence suggests that the phase between XCI and mutated F8 acts as a molecular switch conditioning FVIII:C levels and HA expression in carriers. Fil: Radic, Claudia Pamela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Rossetti, Liliana Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Abelleyro, Miguel Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Tetzlaff, T.. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina Fil: Candela, M.. Academia Nacional de Medicina de Buenos Aires. Instituto de Investigaciones Hematológicas "Mariano R. Castex"; Argentina Fil: Neme, D.. Fundación de la Hemofilia "Alfredo Pavlovsky"; Argentina Fil: Sciuccati, G.. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; Argentina Fil: Bonduel, M.. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; Argentina Fil: Medina Acosta, E.. Universidade Estadual Do Norte Fluminense Darcy Ribeiro; Brasil Fil: Larripa, Irene Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: De Tezanos Pinto, M.. Fundación de la Hemofilia "Alfredo Pavlovsky"; Argentina. Academia Nacional de Medicina de Buenos Aires. Instituto de Investigaciones Hematológicas "Mariano R. Castex"; Argentina Fil: de Brasi, Carlos Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina

Liver transplantation is an accepted treatment modality in the management of MSUD. To our knowledge, ours is only the second successful case to date of a patient with MSUD receiving an allograft from an RLD who is a heterozygous carrier for the disease. In view of the worldwide shortage of available organs for transplantation, heterozygote to homozygote transplantation in the setting of MSUD may provide a viable alternative for those awaiting transplantation. We report on the case of a two-yr-old infant with MSUD, who received a left lateral segment (segments II and III) liver transplant from his mother, a heterozygote carrier of one of the three abnormal genes implicated in MSUD. Post-operative BCAA levels normalized in our patient and remained so on an unrestricted protein diet and during times of physiological stress. To date, this is only the second case of a successful RLD liver transplant in a child with MSUD. Preliminary results indicate that RLD liver transplants are at least equivalent to deceased donor liver transplants in the treatment of MSUD, although longer term follow-up is required. Heterozygote to homozygote RLD transplant in patients with MSUD presents a new pool of potential liver donors.

Introduction Antithrombin resistance (ATR) is a novel thrombotic risk in abnormal prothrombins. A manual ATR assay using Oxyuranus scutellatus (Ox) venom as a prothrombin activator was established for detecting antithrombin-resistant prothrombin. However, this assay was limited because of Ox snake venom availability and its throughput capacity. Here, we have improved the ATR assay using bovine factors Xa and Va (FXa/Va) as prothrombin activators and have optimised assay conditions for an automated instrument (ACL TOP 500). Methods Diluted plasma was incubated with a prothrombin activator mix (phospholipids, CaCl2 , and bovine FXa/Va), followed by inactivation with antithrombin for 10, 20 and 30 minutes. We added a chromogenic substrate S-2238, and assessed changes in absorbance/min at 405 nm. We also adapted assay conditions for ACL TOP 500. Results Optimum conditions for FXa/Va treatment were 6.25% phospholipids, 5 mM CaCL2 , 0.01 μg/mL FXa and 0.1 μg/mL FVa. ATR assay kinetics with the FXa/Va activator was comparable with that with the Ox activator in heterozygous reconstituted plasma with the recombinant wild-type or antithrombin-resistant prothrombin. Using ACL TOP 500, optimum conditions for the FXa/Va treatment were 10.0% phospholipids, 5 mM CaCl2 , 0.02 μg/mL FXa and 0.2 μg/mL FVa. The automated ATR assay with the FXa/Va activator demonstrated good detectability for antithrombin-resistant prothrombin in plasma from a heterozygous carrier with prothrombin Yukuhashi or Belgrade. Conclusion We optimised the ATR assay with the FXa/Va activator and adapted the assay for ACL TOP 500; the assay showed the ability to clearly detect antithrombin-resistant prothrombin in manual and automated procedures.

Background Autosomal recessive hypercholesterolemia (ARH) is a rare inherited lipid disorder. In Sardinia, differently from other world regions, the mutated allele frequency is high. It is caused by mutations in the low-density lipoprotein receptor adaptor protein 1 gene. Fourteen different mutations have been reported so far; in Sardinia, 2 alleles (ARH1 and ARH2) explain most of the cases. Four ARH patients, all carriers of the ARH1 mutation, have been identified in mainland Italy and 2 in Sicily. Objective The objectives of the study were to improve the molecular diagnosis of familial hypercholesterolemia (FH) and to estimate the frequency of the ARH1 allele in 2 free-living Sicilian populations. Methods We sequenced by targeted next-generation sequencing 20 genes related to low-density lipoprotein metabolism in 50 hypercholesterolemic subjects. Subjects from 2 free-living populations from Northern (Ventimiglia Heart Study, 848 individuals) and Southern Sicily (Zabut Zabut Aging Project, 1717 individuals) were genotyped for ARH1 allele. Results We identified 1 homozygous carrier of the ARH1 mutation among the 50 hypercholesterolemic outpatients. Population-based genotyping of ARH1 in 2565 subjects allowed the identification of 1 heterozygous carrier. The overall estimated allele frequency of ARH1 in Sicily was 0.0002 (0.02%). Conclusions The identification of a new case of ARH in Sicily among 50 clinically diagnosed FH highlights the importance of next-generation sequencing analysis as tool to improve the FH diagnosis. Our results also indicate that ARH1 carrier status is present in ∼1:2500 of Sicilian inhabitants, confirming that ARH is extremely rare outside Sardinia.

Two sisters, heterozygous carriers for congenital X-linked protanopia, were diagnosed as normal trichromats by the Rayleigh match on the anomaloscope. The heterozygous state was established by molecular analysis of their visual pigment genes. The normal color match establishes that the spectral sensitivities of their long-wavelength-sensitive (LWS) and middle-wavelength-sensitive (MWS) cone visual photopigments are within normal variability. Their FM 100-hue test error scores were low, demonstrating superior chromatic discrimination. Heterochromatic flicker photometric (HFP) spectral sensitivities were like those of protanopes. The estimated LWS/MWS cone ratios from the HFP data were 0.09 1 and 0.03 1 , compared with ratios in the range of 0.6 1 to 10 1 for typical normal trichromats. Measurements of chromatic grating acuity on chromatically selective backgrounds were performed to study the cone mosaic. The data were consistent with a sparsity of LWS cones. Both protan carriers showed normal spectral sensitivities for all three cone types under cone isolating chromatic adaptation and normal three-peaked curves for increment thresholds on at white pedestal. Hue estimation, run on one carrier was normal. The equilibrium yellow locus was measured in the other carrier and was in the range of normal trichromats. The data indicate that normal color vision can occur even when the LWS/MWS cone ratio is quite abnormal.

Background An increased HbA2 level is the hallmark for identification of β thalassemia carriers. However, in some carriers the level of HbA2 is not typically elevated creating difficulties in making a diagnosis. Methods We describe a family having an affected child referred to us for confirmation of diagnosis of β thalassemia. Results The father has a classical β thalassemia trait and the mother showed typical reduced red cell indices with a high RBC count but the HbA2 level was normal (2.4%). On molecular analysis she was a heterozygous carrier having IVS1 nt 5 (G → C) β thalassemia mutation. Further analysis of δ globin gene showed that the reduction in HbA2 was due to the presence of the δ mutation HbA2 Pelendri [CD 141(Leu → Pro, C T G → C C G)]. Conclusions The diagnosis of a β thalassemia carrier could have been compromised, and states the importance of comprehensive molecular analysis for accurate diagnosis in couples where one partner has β thalassemia trait.

We studied the genetic background of a family with SCA, showing dominant inheritance and anticipation. Muscle histology, POLG1 gene sequence, neuropathology and mitochondrial DNA analyses in a mother and a son showed typical findings for a mitochondrial disorder, and both were shown to be homozygous for a recessive POLG1 mutation, underlying mitochondrial recessive ataxia syndrome, MIRAS. The healthy father was a heterozygous carrier for the same mutation. Recessively inherited MIRAS mutations should be tested in dominantly inherited SCAs cases of unknown cause, as the high carrier frequency of MIRAS may result in two independent introductions of the mutant allele in the family and thereby mimic dominant inheritance.

We report a case of lipoma in the right infraclavicular and axillary area compressing subclavian vein there by presenting with upper extremity deep venous thrombosis (UEDVT) and persistent symptoms of venous congestion. Patient was also found to be a heterozygous carrier of prothrombin 20210 gene mutation. Surgical excision of lipomatous tissue performed after 6 months of anticoagulation resulted in a complete resolution of symptoms.

Background. Newborn screening saves lives, but the way in which parents learn of a positive screening test is also important for adherence with treatment plans and avoidance of psychosocial complications. The first messages provided to parents may be particularly important for understanding, especially when the infant is found to be a heterozygous carrier for sickle cell hemoglobinopathy (SCH) or cystic fibrosis (CF). This study investigated the prevalence of “initially misleading” communication, defined as the inclusion of 1 of 55 “bad-news” content items (eg, the screening test is positive) before any of 39 “good-news” content items (eg, the infant is healthy, normal, a carrier, or otherwise without problems). Methods. As part of a larger study of the content of counseling after newborn genetic screening, we used a quantitative, explicit-criteria method to abstract 59 transcribed conversations between pediatric residents and standardized parents of an “infant” who was found through newborn screening to carry either CF or SCH. Results. Of 59 transcripts, 41 were found to be misleading (at least 1 bad-news content statement before the first good-news content statement). There were significantly more misleading likely-CF-carrier than SCH-carrier transcripts (89.7% vs 50%). Among the misleading transcripts, the mean number of misleading statements was 5.5. The mean distance between the first bad-news and first good-news statements was 28.1 statements (20.5% of the total duration of counseling). Discussion. The high prevalence of misleading content and the time lag before clarification does not bode well for parental understanding of infant carrier status. Future projects should improve curricula for training programs and develop quality-assurance efforts for community clinicians both to improve parental understanding and help assuage society's fears about the safety of genetic screening technologies.

Fragile X (FraX) syndrome is the most common cause of inherited mental retardation. The FraX gene (FMR1) has been cloned, and the mutation causing the disease is now known. We estimated the effect of FraX on dental development in 28 affected boys (aged 4.9-17.6 years) and three carrier girls (aged 5.8, 10.4, and 12.7 years). Dental maturity, assessed on the basis of formation [Demirjian A, Goldstein H. 1976: Ann Hum Biol 3:411-421] and of emergence [Hagg U, Taranger J. 1985: Angle Orthod 55:93-107], was compared with growth in stature and skeletal maturity. The mean relative dental age was advanced in FraX males, based on formation (+1.4 SD) and on emergence (+1.1 SD). More pronounced advancement was seen in younger children. Dental maturity was advanced in heterozygous carrier girls as well. Height and skeletal maturity did not show a similar trend toward advanced development.

We investigated electrophysiologically the unaffected parents of patients with recessive myotonia congenita. We studied 18 families, in nine of which the diagnosis was confirmed by molecular genetics. Brief myotonic discharges were present in at least one parent in 67% of the families. Fathers were more likely than mothers to show these discharges. The difficulty in distinguishing very mildly affected parents with dominant myotonia congenita from the heterozygous carriers of recessive myotonia congenita is stressed.

In this issue of the Journal, Arn et al.1 describe a new clinical entity: ammonia intoxication in otherwise healthy women, particularly in the postpartum period. The entity results from a defect at the X-chromosome locus for the liver-specific urea-cycle enzyme ornithine carbamoyltransferase (also called ornithine transcarbamoylase). The condition is striking not only because of its potentially catastrophic nature — two of the five women reported on died — but also because it occurs in the heterozygous carrier state; these women had one normal ornithine carbamoyltransferase gene in addition to their mutant one. Until now, ornithine carbamoyltransferase deficiency has been known . . .

Involvement of the placenta by glycosphingolipid deposits in Fabry's disease has not been previously reported. We describe the presence of such deposits in the maternal half of a placenta obtained from a heterozygous carrier of the disease.

Leukocytes from 21 obligate carriers in 12 Sanfilippo A families and 49 normal controls were assayed for heparan sulphamidase (EC 3.10.1.1) at 55 degrees C. At this assay temperature the results show an absolute distinction between heterozygous carriers and the normal controls.

Genetically determined C2 deficiency predisposes an individual to recurrent and invasive bacterial infections as well as a variety of rheumatic diseases. Most C2-deficient individuals carry the same 28-bp deletion in the sixth exon of the C2 gene. The present article reports the first prenatal analysis of a sibling of a C2-deficient patient; the sibling was found to be a heterozygous carrier of the 28-bp deletion of C2.

EDITOR,—Linda Laird and colleagues are right in stating that it is important to cater for the needs of families with infants who are found to be carriers of a haemoglobinopathy gene.1 We believe that families should be fully informed when a screening programme detects a heterozygous carrier infant. Since 1992 we have run a selective newborn screening programme in Sandwell (population 295 000; a quarter of births are to couples in which one or both …

The response of plasma progesterone, 17 alpha-hydroxyprogesterone (17-OHP), and cortisol to intravenous ACTH was determined in 16 control subjects and seven sets of parents of children with congenital virilizing adrenal hyperplasia. The baseline and poststimulation concentrations of hormones (of each group) were similar except for those of 17-OHP in the parents which were significantly greater following administration of ACTH. When rates of increase were determined, those of progesterone and 17-OHP but not cortisol were significantly greater in the parents. The combined rate of increase of progesterone and 17-OHP was calculated; 10 of the 14 parents had a combined rate of increase greater than the mean plus two standard deviations of the control group. This test provides a simple method for the detection of some heterozygous carriers for CVAH.

Four males, the sons of 2 sisters, apparently have a new syndrome of mental retardation, seizures and psoriasis. Due to the relationship between the affected males we propose the inheritance to be X-linked recessive although cosegregation of two separate disorders may be occurring. Psoriasis has never been reported as a monogenic disorder. Results of cytogenetic studies, including fra (X) and high-resolution prometaphase analysis, were negative. Steroid sulfatase activities of cultured fibroblasts from 2 surviving affected males were normal. The results of HLA typing of all available relatives did not indicate a strong association between the skin disorder and certain HLA antigens. A healthy sister, who may be heterozygous carrier of the mutant X chromosome, decided on termination of 3 successive pregnancies after prenatal male sex determinations. Her fourth pregnancy with a female fetus is ongoing.

An extended linkage analysis was performed on the large Latin-American kindred with X-linked retinitis pigmentosa (XLRP) and metallic sheen in the heterozygous carrier studied and reported previously by R.L. Nussbaum et al. (1985, Hum. Genet. 70:45-50) and on a smaller family with the same XLRP variant. In these kindreds the XLRP locus shows close linkage with Xp21 marker loci OTC and DXS206. The results of this linkage analysis agree with the observations made by Nussbaum et al. (1985) that an XLRP locus is distal to DXS7.

Females heterozygous for congenital colour vision defects are of interest because they are believed to have cone photoreceptor ratios and cone photopigments that differ from normal. We describe a molecular genetic method to identify protan carriers that involves characterizing the genes that occur in the most upstream position in each of the X-chromosome photopigment gene arrays.

Thin-layer isoelectric focusing was performed on samples of sera from patients with Cystic Fibrosis, siblings and obligate heterozygotes (parents), and children without cystic fibrosis (controls). The protein band with an isoelectric point of pH 5.48, previously reported to be absent in homozygote cystic fibrosis sera, was found to have a pI of 5.25. It was present in approximately one-half of the homozygote and heterozygote sera tested, and absent from 18 percent of control sera. The presence of this band is not therefore a reliable marker for the normal gene, and cannot be used to identify the heterozygous carrier for cystic fibrosis.

Two brothers, 6 and 13 years old, had histidinemia. On the basis of clinical and biochemical observations, the younger boy was considered to have a classical type of the disease, while the older boy had an atypical form characterized by partial impairment of the skin histidase activity and a moderately prolonged half-life of blood histidine. The mother is a heterozygous carrier, while the father and sister seem to be normal.

Summary. Fibroblasts from a heterozygous carrier for the Martin-Bell syndrome, who manifests the fragile site Xq27, were cloned to separate the population carrying the primary defect on the active X chromosome from the population with this defect on the inactive X. Clones with this defect on the active X manifest the fra(X)(q27) whereas clones from the other population are fra(X)-negative (Steinbach et al. 1983b). In this project, the replication status of the X chromosome manifesting the ffa(X)(q27) was studied in seven clones with this defect on the active X. The results obtained on the clones were very similar to the results obtained from uncloned fibroblasts and lymphocytes. In the clones the fragile site was found manifested on the early replicating X in 73 cells and on the late replicating X in four cells. Since the defect is located on the active X chromosome of these cells the .manifestation of the fragile site on the late replicating X suggests that the defect and the fragile site cannot be identical. It is concluded that there is no obligate synteny of this defect and the manifested fragile site.

The incidence of spontaneous abortions in women with glucose-6-phosphate dehydrogenase (G6PD) deficiency was studied. In 78 families where the wife was a heterozygous carrier of G6PD deficiency the percentage of unsuccessful pregnancies with spontaneous abortions occurring in the first trimester was higher (21.7%, calculated from 258 pregnancies) than in the control group (9.3%), calculated from 678 pregnancies.

The frequency of isoniazid slow inactivators is very high among Eqyptians, 82% have more than 0.91 γ/ml of free INH in serum specimens obtained six hours after a single dose of 10 mgm/kgm. The incidence of the allele for INH acetylase enzyme deficiency is estimated at 0.9059 and that of the heterozygous carrier of this allele at 0.1705.

SummaryThe carbazole and naphthoresorcinol methods for hexuronic acid determination have been used to characterize the partially purified acid mucopolysaccharides obtained from urine of normal persons, from patients with gargoylism and from their relatives. The results, expressed as a ratio of carbazole to naphthoresorcinol hexuronic acid, demonstrated a similar abnormal qualitative excretion of chondroitin sulfate B by patients with gargoylism. by one or both parents, and by some of their other relatives. Occurrence of an abnormal qualitative excretion of chondroitin sulfate B in the clinically normal relatives of patients with gargoylism probably indicates the heterozygous carrier state of the disease.

Arylsulfatase A activity in leukocytes from patients and from their close relatives was investigated in three families with metachromatic leukodystrophy. The activity of arylsulfatase A in leukocytes from three patients with metachromatic leukodystrophy was approximately one tenth of the mean control value. The enzyme activity in leukocytes from the parents of affected patients and from some of their relatives was approximately half that found in control subjects, demonstrating a gene-dose effect. There appeared to be no overlap between the enzyme activities in leukocytes from the parents of patients and from normal individuals. These findings suggest that the heterozygous carrier state in metachromatic leukodystrophy could be predicted by the assay of arylsulfatase A in leukocytes and autosomal recessive mode of inheritance may be assumed.

The heterozygous carrier state of a rare hereditary disease, acatalasemia, has been defined biochemically. Affected homozygotes have no blood catalase activity, whereas heterozygotes show activities intermediate between this inactivity and the activity of normal controls, without overlap. Pedigrees show a high frequency of consanguineous marriages.