NGS-based expanded carrier screening for genetic disorders in North Indian population reveals unexpected results - a pilot study.

BACKGROUND: To determine the carrier frequency and pathogenic variants of common genetic disorders in the north Indian population by using next generation sequencing (NGS). METHODS: After pre-test counselling, 200 unrelated individuals (including 88 couples) were screened for pathogenic variants in 88 genes by NGS technology. The variants were classified as per American College of Medical Genetics criteria. Pathogenic and likely pathogenic variants were subjected to thorough literature-based curation in addition to the regular filters. Variants of unknown significance were not reported. Individuals were counselled explaining the implications of the results, and cascade screening was advised when necessary. RESULTS: Of the 200 participants, 52 (26%) were found to be carrier of one or more disorders. Twelve individuals were identified to be carriers for congenital deafness, giving a carrier frequency of one in 17 for one of the four genes tested (SLC26A4, GJB2, TMPRSS3 and TMC1 in decreasing order). Nine individuals were observed to be carriers for cystic fibrosis, with a frequency of one in 22. Three individuals were detected to be carriers for Pompe disease (frequency one in 67). None of the 88 couples screened were found to be carriers for the same disorder. The pathogenic variants observed in many disorders (such as deafness, cystic fibrosis, Pompe disease, Canavan disease, primary hyperoxaluria, junctional epidermolysis bullosa, galactosemia, medium chain acyl CoA deficiency etc.) were different from those commonly observed in the West. CONCLUSION: A higher carrier frequency for genetic deafness, cystic fibrosis and Pompe disease was unexpected, and contrary to the generally held view about their prevalence in Asian Indians. In spite of the small sample size, this study would suggest that population-based carrier screening panels for India would differ from those in the West, and need to be selected with due care. Testing should comprise the study of all the coding exons with its boundaries in the genes through NGS, as all the variants are not well characterized. Only study of entire coding regions in the genes will detect carriers with adequate efficiency, in order to reduce the burden of genetic disorders in India and other resource poor countries.

Identification and characterization of 30 novel pathogenic variations in 69 unrelated Indian patients with Mucolipidosis Type II and Type III.

Mucolipidosis (ML) (OMIM 607840 & 607838) is a rare autosomal recessive inherited disorder that occurs due to the deficiency of golgi enzyme uridine diphosphate (UDP)- N-acetylglucosamine-1-phosphotransferase (GlcNAc-phosphotransferase) responsible for tagging mannose-6-phosphate for proper trafficking of lysosomal enzymes to lysosomes. Variants in GlcNAc-phosphotransferase (GNPTAB (α, ß subunits) and GNPTG (γ subunits) are known to result in impaired targeting of lysosomal enzymes leading to Mucolipidosis (ML) Type II or Type III. We analyzed 69 Indian families of MLII/III for clinical features and molecular spectrum and performed in silico analysis for novel variants. We identified 38 pathogenic variants in GNPTAB and 5 pathogenic variants in GNPTG genes including missense, frame shift, deletion, duplication and splice site variations. A total of 26 novel variants were identified in GNPTAB and 4 in GNPTG gene. In silico studies using mutation prediction software like SIFT, Polyphen2 and protein structure analysis further confirmed the pathogenic nature of the novel sequence variants detected in our study. Except for a common variant c.3503_3504delTC in early onset MLII, we could not establish any other significant genotype and phenotype correlation. This is one of the largest studies reported till date on Mucolipidosis II/III in order to identify mutation spectrum and any recurrent mutations specific to the Indian ethnic population. The mutational spectrum information in Indian patients will be useful in better genetic counselling, carrier detection and prenatal diagnosis for patients with ML II/III.

Unique skeletal manifestations in patients with Primrose syndrome.

Primrose syndrome (OMIM 259050) is a rare disorder characterised by macrocephaly with developmental delay, a recognisable facial phenotype, altered glucose metabolism, and other features such as sensorineural hearing loss, short stature, and calcification of the ear cartilage. It is caused by heterozygous variants in ZBTB20, a member of the POK family of transcription repressors. Recently, this gene was shown to have a role in skeletal development through its action on chondrocyte differentiation by repression of SOX9. We describe five unrelated patients with Primrose syndrome and distinct skeletal features including multiple Wormian bones, platybasia, bitemporal bossing, bathrocephaly, slender bones, epiphyseal and spondylar dysplasia. The radiological abnormalities of the skull and the epiphyseal dysplasia were the most consistent findings. This novel constellation of skeletal features expands the phenotypic spectrum of the disorder.

Expanding the phenotypic and genotypic spectrum of Wiedemann-Steiner syndrome: First patient from India.

Wiedemann-Steiner syndrome (WWS) is a rare disorder characterized by hypotonia, postnatal growth restriction, striking facial dysmorphism, and hirsutism. It is caused by heterozygous pathogenic variants in KMT2A. This gene has an established role in histone methylation, which explains the overlap of WWS with syndromes caused by genes involved in chromatin remodeling. We describe an infant with a novel single base pair deletion in KMT2A with features consistent with WWS, as well as additional features of stenosis of aqueduct of Sylvius and broad toes. The usefulness of Face2Gene as a tool for identification of dysmorphology syndromes is discussed, as in this patient, it suggested WWS as the top candidate disorder. To the best of our knowledge, this is the first patient of WWS reported from India, with a novel genotype and expanded phenotype.

Genetic analysis of familial hypercholesterolemia in Asian Indians: A single-center study.

BACKGROUND: Familial hypercholesterolemia (FH), an autosomal codominant disorder characterized by very high low-density lipoprotein cholesterol, is strongly associated with premature coronary artery disease. OBJECTIVES: Molecular landscape of FH in Asian Indians is not well studied, although this ethnic group comprises a large proportion of the world population. Knowledge of mutations in these groups is useful for identifying persons affected with FH, saving their lives, and cascade screening in their relatives. METHODS: Potential cases of FH (n = 100) were identified by criteria adapted for the Indian population from Dutch Lipid Clinic Network criteria. Pathogenic variants were analyzed in LDLR, APOB 100 (exons 26 and 29), PCSK9, and APOE genes using Sanger sequencing and multiplex ligation-dependent probe amplification technique. Cases in whom there were no pathogenic variants were tested by next-generation sequencing using a targeted panel of genes. RESULTS: Thirty-eight pathogenic variants were identified in 47 of 100 unrelated probands. Of these variants, 33 were identified in LDLR, 3 in APOB, and 2 in PCSK9 genes. Ten pathogenic variants were novel. Mutations were detected in 91.4% of those subjects classified as definite, 40% as probable, and in 18.8% as possible FH cases based on modified Dutch Lipid Clinic Network criteria. A likely founder mutation in intron 10 (c.1587-1G>A) of LDLR gene was observed in 6 North Indian families. The conventional pathogenic variants in APOB and PCSK9 genes and those previously reported in LDLR gene among Asian Indians were not detected in this cohort. CONCLUSION: This study demonstrates genetic heterogeneity of FH in India. The variants observed were different from those described in Western populations. Next-generation sequencing technology helped identify new mutations in APOB gene, suggesting that in less-studied populations, it is better to sequence the whole gene rather than test for specific mutations.

Sialidosis type II: Expansion of phenotypic spectrum and identification of a common mutation in seven patients.

Sialidosis, an autosomal recessive disorder, is characterized by progressive lysosomal storage of sialylated glycopeptides and oligosaccharides. It occurs as a result of biallelic mutations in the NEU1 gene. Sialidosis is traditionally classified as a milder, late-onset type I and a severe early-onset type II disease. The presence of a cherry-red spot is a well-established ophthalmological clue to the disorder. We present a clinical-radiological report of seven unrelated patients with molecularly confirmed sialidosis type II. To the best of our knowledge, This is the largest reported series of patients with Sialidosis type II. A novel, previously unreported ophthalmic phenotype of bulls-eye maculopathy, is described. All seven phenotypically heterogeneous patients had the same pathogenic variant (c.679G > A; p.Gly227Arg) at a homozygous level in the NEU1 gene. We propose that this is a common mutation in north Indians for this rare disorder. We also observed an overlap of symptoms and a continuum of phenotypes in type I and II Sialidosis.

Co-inheritance of pathogenic variants in PKD1 and PKD2 genes presenting as severe antenatal phenotype of autosomal dominant polycystic kidney disease.

Autosomal dominant polycystic kidney disease (ADPKD) is caused by pathogenic variants in either PKD1 or PKD2 genes. Disease severity is dependent on various factors including the presence of modifier genes. We describe a family with recurrent foetal presentation of ADPKD due to co-inheritance of pathogenic variants in both PKD1 [c.3860T > C; p.(Leu1287Pro)] and PKD2 [(c.1000C > A; p.(Pro334Thr)] genes. Familial segregation studies revealed the mother and the father to be heterozygous for the same variants in the PKD1 and PKD2 genes, respectively, as found in the foetus. Renal ultrasonography detected evidence of cystic disease in the mother and two of her family members. No cysts were detected in the father, however the paternal grandfather died of renal cystic disease. The absence of disease in the father can be explained by the phenomenon of incomplete penetrance, or Knudson's two-hit hypothesis of cystogenesis in the grandfather. This case underscores the importance of sequencing PKD2 gene even in the presence of a familial PKD1 variant, as well as genetic testing of the cysts for evidence of the second hit.

Mutation-Proved Clouston Syndrome in a Large Indian Family with a Variant Phenotype.

Hereditary ectodermal dysplasias, a group of disorders affecting skin, hair, nails, and teeth, consist of two main clinical forms - hypohidrotic and hidrotic. Clouston syndrome is a hidrotic ectodermal dysplasia characterized by a triad of generalized hypotrichosis, palmoplantar hyperkeratosis, and nail dystrophy. This paper reports a large Indian family with Clouston syndrome but with the absence of palmoplantar keratoderma, one of the features of the typical triad, thus representing phenotypic heterogeneity, in spite of the presence of a common known mutation in GJB6 gene (p.Gly11Arg).

Familial Hypercholesterolemia: Cascade Screening in Children and Relatives of the Affected.

OBJECTIVE: Familial Hypercholesterolemia (FH) is an inherited disorder of lipid metabolism characterized by very high low density lipoprotein (LDL) cholesterol since birth, resulting in premature atherosclerosis and coronary artery disease (CAD). Cascade screening of children and family members of proven FH individuals can identify more subjects who have high LDL cholesterol or the family mutation and appropriate intervention can reduce their risk of atherosclerosis and prevent its complications. METHODS: Cascade screening by molecular testing, was carried out in 133 family members, comprising 24 children, of 31 probands with FH having a pathogenic mutation in LDLR/ApoB gene. Lipid profiles were obtained in 44 family members including 11 children. RESULTS: Of 133 family members tested, 88 (66.1%) were identified to carry the family mutation. Twelve of these were children below 18 y of age and 76 were adults. CAD was present in 15 (11.2%) family members and 63(47.4%) family members, including nine children, were already on Lipid Lowering Therapy. CONCLUSIONS: Cascade screening led to identification of 88 new cases, with a pathogenic mutation, who were at a very high risk of developing premature CAD. The authors identified 12 children with family specific mutation, out of which 9 were initiated on low dose statin therapy. Four homozygous children were treated with high dose statins because of substantially increased risk of CAD. Cascade screening, therefore, proved to be a successful initiative towards primary prevention of CAD in India.

Mutations in GREB1L Cause Bilateral Kidney Agenesis in Humans and Mice.

Congenital anomalies of the kidney and urinary tract (CAKUT) constitute a major cause of chronic kidney disease in children and 20% of prenatally detected anomalies. CAKUT encompass a spectrum of developmental kidney defects, including renal agenesis, hypoplasia, and cystic and non-cystic dysplasia. More than 50 genes have been reported as mutated in CAKUT-affected case subjects. However, the pathophysiological mechanisms leading to bilateral kidney agenesis (BKA) remain largely elusive. Whole-exome or targeted exome sequencing of 183 unrelated familial and/or severe CAKUT-affected case subjects, including 54 fetuses with BKA, led to the identification of 16 heterozygous variants in GREB1L (growth regulation by estrogen in breast cancer 1-like), a gene reported as a target of retinoic acid signaling. Four loss-of-function and 12 damaging missense variants, 14 being absent from GnomAD, were identified. Twelve of them were present in familial or simplex BKA-affected case subjects. Female BKA-affected fetuses also displayed uterus agenesis. We demonstrated a significant association between GREB1L variants and BKA. By in situ hybridization, we showed expression of Greb1l in the nephrogenic zone in developing mouse kidney. We generated a Greb1l knock-out mouse model by CRISPR-Cas9. Analysis at E13.5 revealed lack of kidneys and genital tract anomalies in male and female Greb1l-/- embryos and a slight decrease in ureteric bud branching in Greb1l+/- embryos. We showed that Greb1l invalidation in mIMCD3 cells affected tubulomorphogenesis in 3D-collagen culture, a phenotype rescued by expression of the wild-type human protein. This demonstrates that GREB1L plays a major role in early metanephros and genital development in mice and humans.

Next-Generation Sequencing Reveals a Nonsense Mutation (p.Arg364Ter) in MRE11A Gene in an Indian Patient with Familial Breast Cancer.

BACKGROUND: The MRN complex consisting of MRE11A-RAD50-NBS1 proteins is involved in the repair of double-strand breaks, and mutations in genes coding for the MRN complex have been identified in families with breast and ovarian cancer. CASE REPORT: In a BRCA-negative family with positive history of breast and endometrial cancer, next-generation sequencing-based panel testing identified a mutation in the MRE11A gene (NM_005590 c.1090C>T: p.Arg364Ter). This mutation results in a shorter mutated protein lacking 2 DNA binding domains (the GAR domain and the RAD50 binding site), abolishing the function of protein. CONCLUSION: This case provides insight into the role of the MRE11A gene in causing breast cancer susceptibility in families, and supports the use of multigene panel testing in cases with hereditary predisposition to breast cancer.

Relationship Between Morphology, Euploidy and Implantation Potential of Cleavage and Blastocyst Stage Embryos.

AIM: The aim of this study was to investigate the relationship between the morphology, euploidy and implantation rate of cleavage stage and blastocyst stage embryos. SETTING: Institution-based, tertiary care in-vitro fertilization centre. STUDY DESIGN: This study included a retrospective data analysis of 306 embryos: 154 cleavage stage embryos and 152 blastocysts that underwent biopsy on day 3 and day 5/6, respectively, which were subsequently screened for aneuploidy by array comparative genomic hybridization analysis. MATERIALS AND METHODS: Both cleavage stage and blastocyst stage embryos were categorized according to their morphology into the following three groups: good, average and poor. In addition, blastocysts were categorized into day 5 and day 6 embryos on the basis of their developmental rate. RESULTS: The euploidy rate was found to be significantly higher for blastocysts with good morphology as compared to those with poor morphology, with 73.2, 50 and 40.5% euploid embryos in the good, average and poor morphology groups, respectively (P = 0.001). No significant association was found between day 3 embryo morphology and euploidy rates with 40.6, 29.3 and 25.8% euploid embryos in the three groups, respectively (P = 0.254). The implantation rates, as per morphology, for the transferred euploid cleavage stage and blastocyst stage embryos were 43.8, 37.5 and 0% (P = 0.354) and 51.7, 71.4 and 66.7% (P = 0.562) in the good, average and poor morphology groups, respectively. The euploidy rate for day 5 blastocysts was significantly higher (70% vs. 34.1%, P < 0.001) than that of day 6 blastocysts, but the implantation rate was similar in both the groups (58.8 and 50%, respectively). The miscarriage rates for the euploid cleavage stage and the blastocysts stage embryos were 18.2 and 8.3% (P = 0.575), respectively. CONCLUSION: Blastocyst morphology and the rate of development were found to be significantly associated with euploidy, whereas cleavage stage morphology was not. The implantation rates of the good quality, euploid cleavage stage embryos were higher than that of the poor quality embryos. The implantation rates were similar for all transferred euploid blastocysts, irrespective of their morphology or the rate of development.

Spectrum of mutations in homozygous familial hypercholesterolemia in India, with four novel mutations.

BACKGROUND AND AIMS: Homozygous familial hypercholesterolemia (FH) is a rare but serious, inherited disorder of lipid metabolism characterized by very high total and LDL cholesterol levels from birth. It presents as cutaneous and tendon xanthomas since childhood, with or without cardiac involvement. FH is commonly caused by mutations in three genes, i.e. LDL receptor (LDLR), apolipoprotein B (ApoB) and PCSK9. We aimed to determine the spectrum of mutations in cases of homozygous FH in Asian Indians and evaluate if there was any similarity to the mutations observed in Caucasians. METHODS: Sixteen homozygous FH subjects from eleven families were analyzed for mutations by Sanger sequencing. Large rearrangements in LDLR gene were evaluated by multiplex ligation probe dependent amplification (MLPA) technique. RESULTS: Ten mutations were observed in LDLR gene, of which four mutations were novel. No mutation was detected in ApoB gene and common PCSK9 mutation (p.D374Y). Fourteen cases had homozygous mutations; one had compound heterozygous mutation, while no mutation was detected in one clinically homozygous case. We report an interesting "Triple hit" case with features of homozygous FH. CONCLUSIONS: The spectrum of mutations in the Asian Indian population is quite heterogeneous. Of the mutations identified, 40% were novel. No mutation was observed in exons 3, 9 and 14 of LDLR gene, which are considered to be hot spots in studies done on Asian Indians in South Africa. Early detection followed by aggressive therapy, and cascade screening of extended families has been initiated to reduce the morbidity and mortality in these patients.

Does Formaldehyde Increase Cell Free DNA in Maternal Plasma Specimens?

BACKGROUND: There have been conflicting observations reported in the literature regarding the effects of formaldehyde in the recovery of cell free fetal DNA (CFF DNA) from maternal plasma. The aim of the present study was to assess the effect of formaldehyde treatment on circulating cell free DNA. METHODS: We conducted this study using blood specimens collected from 11 pregnant women, each of whom was carrying a male fetus. DYS14 and HBB real time assays were performed to quantify fetal and total circulating cell free DNA from formaldehyde treated and untreated maternal plasma specimens, respectively. RESULTS: The concentration of total circulating cell free DNA in formaldehyde-treated maternal plasma was reduced, compared with untreated maternal plasma (n = 11; P = .02). The percentage of CFF DNA between formaldehyde-treated and untreated maternal plasma specimens did not differ significantly (n = 11; P = .15). CONCLUSION: Addition of formaldehyde does not significantly enhance the proportion of cell free fetal DNA when blood specimens are processed without delay.

Preimplantation genetic screening for all 24 chromosomes by microarray comparative genomic hybridization significantly increases implantation rates and clinical pregnancy rates in patients undergoing in vitro fertilization with poor prognosis.

CONTEXT: A majority of human embryos produced in vitro are aneuploid, especially in couples undergoing in vitro fertilization (IVF) with poor prognosis. Preimplantation genetic screening (PGS) for all 24 chromosomes has the potential to select the most euploid embryos for transfer in such cases. AIM: To study the efficacy of PGS for all 24 chromosomes by microarray comparative genomic hybridization (array CGH) in Indian couples undergoing IVF cycles with poor prognosis. SETTINGS AND DESIGN: A retrospective, case-control study was undertaken in an institution-based tertiary care IVF center to compare the clinical outcomes of twenty patients, who underwent 21 PGS cycles with poor prognosis, with 128 non-PGS patients in the control group, with the same inclusion criterion as for the PGS group. MATERIALS AND METHODS: Single cells were obtained by laser-assisted embryo biopsy from day 3 embryos and subsequently analyzed by array CGH for all 24 chromosomes. Once the array CGH results were available on the morning of day 5, only chromosomally normal embryos that had progressed to blastocyst stage were transferred. RESULTS: The implantation rate and clinical pregnancy rate (PR) per transfer were found to be significantly higher in the PGS group than in the control group (63.2% vs. 26.2%, P = 0.001 and 73.3% vs. 36.7%, P = 0.006, respectively), while the multiple PRs sharply declined from 31.9% to 9.1% in the PGS group. CONCLUSIONS: In this pilot study, we have shown that PGS by array CGH can improve the clinical outcome in patients undergoing IVF with poor prognosis.

Spectrum of SMPD1 mutations in Asian-Indian patients with acid sphingomyelinase (ASM)-deficient Niemann-Pick disease.

Acid sphingomyelinase (ASM)-deficient Niemann-Pick disease is an autosomal recessive lysosomal storage disorder caused by biallelic mutations in the SMPD1 gene. To date, around 185 mutations have been reported in patients with ASM-deficient NPD world-wide, but the mutation spectrum of this disease in India has not yet been reported. The aim of this study was to ascertain the mutation profile in Indian patients with ASM-deficient NPD. We sequenced SMPD1 in 60 unrelated families affected with ASM-deficient NPD. A total of 45 distinct pathogenic sequence variants were found, of which 14 were known and 31 were novel. The variants included 30 missense, 4 nonsense, and 9 frameshift (7 single base deletions and 2 single base insertions) mutations, 1 indel, and 1 intronic duplication. The pathogenicity of the novel mutations was inferred with the help of the mutation prediction software MutationTaster, SIFT, Polyphen-2, PROVEAN, and HANSA. The effects of the identified sequence variants on the protein structure were studied using the structure modeled with the help of the SWISS-MODEL workspace program. The p. (Arg542*) (c.1624C>T) mutation was the most commonly identified mutation, found in 22% (26 out of 120) of the alleles tested, but haplotype analysis for this mutation did not identify a founder effect for the Indian population. To the best of our knowledge, this is the largest study on mutation analysis of patients with ASM-deficient Niemann-Pick disease reported in literature and also the first study on the SMPD1 gene mutation spectrum in India. © 2016 Wiley Periodicals, Inc.

LYRM7 mutations cause a multifocal cavitating leukoencephalopathy with distinct MRI appearance.

This study focused on the molecular characterization of patients with leukoencephalopathy associated with a specific biochemical defect of mitochondrial respiratory chain complex III, and explores the impact of a distinct magnetic resonance imaging pattern of leukoencephalopathy to detect biallelic mutations in LYRM7 in patients with biochemically unclassified leukoencephalopathy. 'Targeted resequencing' of a custom panel including genes coding for mitochondrial proteins was performed in patients with complex III deficiency without a molecular genetic diagnosis. Based on brain magnetic resonance imaging findings in these patients, we selected additional patients from a database of unclassified leukoencephalopathies who were scanned for mutations in LYRM7 by Sanger sequencing. Targeted sequencing revealed homozygous mutations in LYRM7, encoding mitochondrial LYR motif-containing protein 7, in four patients from three unrelated families who had a leukoencephalopathy and complex III deficiency. Two subjects harboured previously unreported variants predicted to be damaging, while two siblings carried an already reported pathogenic homozygous missense change. Sanger sequencing performed in the second cohort of patients revealed LYRM7 mutations in three additional patients, who were selected on the basis of the magnetic resonance imaging pattern. All patients had a consistent magnetic resonance imaging pattern of progressive signal abnormalities with multifocal small cavitations in the periventricular and deep cerebral white matter. Early motor development was delayed in half of the patients. All patients but one presented with subacute neurological deterioration in infancy or childhood, preceded by a febrile infection, and most patients had repeated episodes of subacute encephalopathy with motor regression, irritability and stupor or coma resulting in major handicap or death. LYRM7 protein was strongly reduced in available samples from patients; decreased complex III holocomplex was observed in fibroblasts from a patient carrying a splice site variant; functional studies in yeast confirmed the pathogenicity of two novel mutations. Mutations in LYRM7 were previously found in a single patient with a severe form of infantile onset encephalopathy. We provide new molecular, clinical, and neuroimaging data allowing us to characterize more accurately the molecular spectrum of LYRM7 mutations highlighting that a distinct and recognizable magnetic resonance imaging pattern is related to mutations in this gene. Inter- and intrafamilial variability exists and we observed one patient who was asymptomatic by the age of 6 years.

Inherited metabolic disorders: prenatal diagnosis of lysosomal storage disorders.

OBJECTIVE: To offer accurate prenatal diagnosis of lysosomal storage disorders in early pregnancy. METHOD: Prenatal enzymatic diagnoses of Gaucher, Fabry, Pompe, Niemann Pick A/B, Tay Sach, Sandoff, GM1, mucoplysaccharidoses, Wolman, Krabbe, Metachromatic leukodystrophy and Batten diseases were made in uncultured chorionic villi samples by fluorometric/spectrophotometric methods. RESULTS: Of 331 prenatal enzymatic diagnosis, 207 fetuses (67%) were normal and 124 (37%) were affected. The interpretation of affected, normal and carrier fetuses was done using their respective reference ranges as well as % enzyme activity of normal mean. The prenatal molecular confirmation was feasible in 43 biochemically diagnosed fetuses. Of the 207 normal reported fetuses, post natal enzymatic confirmation was done in 23 babies, clinical status of another 165 babies was assessed as unaffected via questionnaire on telephone and 19 were lost to follow-up. In affected pregnancies, 123 opted for termination of which 44 were confirmed enzymatically after abortion. A single false positive was determined to be a carrier by prenatal mutation analysis and carried to term. CONCLUSION: We recommend uncultured chorionic villi for reliable prenatal enzymatic diagnosis of various lysosomal storage disorders on account of the low rate of false positive (0.5%) and false negative (2.2%) results.

Molecular Diagnosis of Hereditary Fructose Intolerance: Founder Mutation in a Community from India.

Hereditary fructose intolerance (HFI) is a difficult-to-confirm diagnosis, requiring either invasive liver biopsy-enzyme assay or potentially hazardous fructose challenge test or expensive molecular genetic analysis. Therefore, worldwide there has been a trend towards finding "common mutations" in distinct ethnic groups to simplify the process of diagnosis. The nonspecific presentation of the disease often leads to diagnostic confusion with other metabolic liver disorders such as glycogenoses, galactosemia, and tyrosinemia. This leads to much delay in diagnosis with consequent harm to the patient.We report mutations in the ALDOB gene, from eleven Indian patients, seven of whom belong to the Agarwal community. Six patients from the Agarwal community and two non-Agarwal patients harbored one novel mutation, c.324+1G>A (five homozygous and one heterozygous), in the ALDOB gene. Haplotyping performed in families confirmed a founder effect. The community has been known to harbor founder mutations in other genes such as the MLC1, PANK2, and CAPN3 genes, thus providing another evidence for a founder effect in the community in case of HFI. This may pave the path for a simpler and quicker test at least for this community in India. In addition to the founder mutation, we report four other novel mutations, c.112+1delG, c.380-1G>A, c.677G>A, and c.689delA, and a previously reported mutation, c.1013C>T, in the cohort from India.