Expanding the spectrum of ADNP-related disorder-Antenatally diagnosed congenital diaphragmatic hernia and a novel de novo mutation in ADNP gene.

De novo heterozygous ADNP variants have been associated with a complex neurological phenotype characterized primarily by neurodevelopmental delay. Cardiac and renal anomalies have additionally been observed in a few patients. All reported cases to date have been ascertained postnatally. Congenital diaphragmatic hernia (CDH) has been previously observed in one child diagnosed with a de novo ADNP-related neurodevelopmental disorder. We report a fetus who presented with syndromic CDH associated with a de novo heterozygous ADNP variant.

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.

First International Conference on RASopathies and Neurofibromatoses in Asia: Identification and advances of new therapeutics.

The neurofibromatoses, which include neurofibromatosis type I (NF1), neurofibromatosis type II (NF2), and schwannomatosis, are a group of syndromes characterized by tumor growth in the nervous system. The RASopathies are a group of syndromes caused by germline mutations in genes that encode components of the RAS/mitogen-activated protein kinase (MAPK) pathway. The RASopathies include NF1, Noonan syndrome, Noonan syndrome with multiple lentigines, Costello syndrome, cardio-facio-cutaneous syndrome, Legius syndrome, capillary malformation arterio-venous malformation syndrome, and SYNGAP1 autism. Due to their common underlying pathogenetic etiology, all these syndromes have significant phenotypic overlap of which one common feature include a predisposition to tumors, which may be benign or malignant. Together as a group, they represent one of the most common multiple congenital anomaly syndromes estimating to affect approximately one in 1000 individuals worldwide. The subcontinent of India represents one of the largest populations in the world, yet remains underserved from an aspect of clinical genetics services. In an effort to bridge this gap, the First International Conference on RASopathies and Neurofibromatoses in Asia: Identification and Advances of New Therapeutics was held in Kochi, Kerala, India. These proceedings chronicle this timely and topical international symposium directed at discussing the best practices and therapies for individuals with neurofibromatoses and RASopathies.

Analysis of 26 amino acids in human plasma by HPLC using AQC as derivatizing agent and its application in metabolic laboratory.

The present study reports the simultaneous analysis of 26 physiological amino acids in plasma along with total cysteine and homocysteine by high-performance liquid chromatography (HPLC) employing 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) as precolumn derivatizing reagent. Separations were carried out using Lichrospher 100 RP-18e (5 µm) 250 × 4.0 mm column connected to 100 CN 4.0 × 4.0 mm guard column on a quaternary HPLC system and run time was 53 min. Linearity of the peak areas for different concentrations ranging from 2.5 to 100 pmol/µL of individual amino acids was determined. A good linearity (R (2) > 0.998) was achieved in the standard mixture for each amino acid. Recovery of amino acids incorporated at the time of derivatization ranged from 95 to 106 %. Using this method we have established the normative data of amino acids in plasma, the profile being comparable to the range reported in literature and identified cases of classical homocystinuria, cobalamin defect/deficiency, non-ketotic hyperglycinemia, hyperprolinemia, ketotic hyperglycinemia, urea cycle defect and maple syrup urine disease.

Results of comprehensive genetic testing in patients presenting to a multidisciplinary inherited heart disease clinic in India.

OBJECTIVES: This study aims to analyze the results of comprehensive genetic testing in patients presenting to a dedicated multidisciplinary inherited heart disease clinic in India. METHODS: All patients presenting to our clinic from August 2017 to October 2023 with a suspected inherited heart disease and consenting for genetic testing were included. The probands were grouped into familial cardiomyopathies namely hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), arrhythmogenic cardiomyopathy (ACM) and peripartum cardiomyopathy (PPCM), channelopathies namely congenital long QT syndrome (LQTS) and Brugada syndrome (BrS), and heritable connective tissue disorder namely Marfan Syndrome (MFS). Next generation sequencing (NGS) was used, and pre-test and post-test counseling were provided to probands and cascade screening offered to relatives. RESULTS: Mean age of the subjects (n = 77; 48 probands, 29 relatives) was 43 ± 18 years, 68 % male and 44 % symptomatic, with 36 HCM, 3 DCM, 3 ACM, 1 PPCM, 3 LQTS, 1 BrS and 1 MFS probands. The diagnostic yield of NGS-based genetic testing was 31 %; variants of uncertain significance (VUS) were identified in 54 %; and 15 % were genotype-negative. Twenty-nine relatives from 18 families with HCM (n = 12), DCM (n = 3), ACM (n = 2) and MFS (n = 1) underwent genetic testing. The genotype positive probands/relatives and VUS carriers with strong disease phenotype and/or high risk variant were advised periodic follow-up; the remaining probands/relatives were discharged from further clinical surveillance. CONCLUSIONS: Genetic testing guides treatment and follow-up of patients with inherited heart diseases and should be carried out in dedicated multidisciplinary clinics with expertise for counseling and cascade screening of family members.

Exome sequencing and microarray identified a novel large exonic deletion in SYT2 gene in an ultra-rare case with recessive CMS type 7.

Congenital myasthenic syndromes (CMSs) are a diverse group of diseases that have an underlying defect in transmission of signals from nerve cells to muscles that lead to muscular weakness. A 13-year-old male child born of consanguineous parents with profound motor developmental delay and normal cognition was referred to us. The younger male sibling aged 9 months was similarly affected. Electromyography (EMG) and nerve conduction studies revealed CMS. Clinical exome sequencing revealed a novel large deletion including the exons 2 to 9 of SYT2 gene which confirmed the diagnosis of presynaptic CMS type 7 in the siblings. The deletion was confirmed on a chromosomal exon microarray. The parents were confirmed carriers of the same mutation and were normal on clinical and EMG studies. This is the second case of CMS type 7 described with a large deletion of SYT2 gene, a first case with SYT2 gene mutation from India and overall 10th recessive case in the world.

Detection of IEMs by Mass Spectrometry Techniques in High-Risk Children: A Pilot Study.

OBJECTIVES: To determine the incidence and types of inborn errors of metabolism (IEMs) in high-risk children using mass spectrometry techniques. METHODS: Children considered high-risk for IEM were screened for metabolic diseases during a 3-y period. Dried blood spots and urine samples were analyzed by tandem mass spectrometry (LC-MS/MS) and gas chromatograph-mass spectrometry (GCMS). Samples with abnormal amino acids were confirmed by high-performance liquid chromatography (HPLC). RESULTS: Eight hundred and twenty-two suspected cases were evaluated; of which, 87 possible cases of IEMs were identified. Homocystinuria (n = 51) was the most common IEM detected followed by biotinidase deficiency (n = 7), glutaric aciduria type 1 (n = 7), and carnitine uptake defect (n = 6). Overall, there were 45 (51.7%) cases of organic acidemia, 31 cases (35.6%) of amino acid defect, 9 (10.3%) cases of fatty-acid oxidation disorders, and 2 (2.3%) cases of probable mitochondrial disorder. CONCLUSION: IEMs are common in India, with a hospital-based incidence of 1 in approximately 6642 among high-risk children. Screening of high-risk children by mass spectrometry techniques is a valuable strategy for early diagnosis of IEMs where universal newborn screening is not yet available.

Report of two brothers with short stature, microcephaly, mental retardation, and retinoschisis-A new mental retardation syndrome?

Involvement of genes on the X-chromosome as a cause of mental retardation has been recognized for a long time. X-linked phenotypes of mental retardation have been divided into non-syndromic and syndromic based on associated manifestations. At present, more than 140 syndromic X-linked mental retardation (XLMR) conditions have been reported and a causative gene mutation has been identified in almost half of these. Here, we report on two brothers with short stature, microcephaly, severe mental retardation, and retinoschisis. Results of karyotype analysis, fragile-X and neuroimaging studies were normal. Fundus examination showed bilateral retinoschisis at variable stages in both sibs. X-linked retinoschisis is a retinal dystrophy caused by mutations in the RS1 gene at Xp22.1, which lead to splitting of the neural retina and reduced visual acuity in affected men. However, as yet there have been no reports of mental retardation in X-linked retinoschisis although genetic loci for XLMR and short stature have been mapped to Xp22.1. Sequencing and microarray analysis failed to find any alteration of RS1 gene or copy number alteration in the region. In addition, genotype analysis of Xp22.1 provided evidence against linkage to this region. The associated findings of retinoschisis and mental retardation in two brothers suggest a new mental retardation syndrome likely to be an X linked trait.

A Young Girl With Bronchiectasis and Elevated Sweat Chloride.

CASE PRESENTATION: A 14-year old girl presented with history of productive cough since the age of 3 years. For the past 6 years, she complained of chest tightness and wheezing. There was also nasal stuffiness and discharge for the past 6 years. She denied history of hemoptysis, ear discharge, or chest pain. There was no history of respiratory distress at the time of birth. Her brother also suffered from productive cough and wheezing since the age of 3 years. However, both her parents were asymptomatic.

Response to zolendronic acid in children with type III osteogenesis imperfecta.

Osteogenesis imperfecta (OI) is a common genetic disorder that manifests with intrauterine or pre- or postnatal fractures, blue sclera, and deafness. Various treatments for the management of OI have been tried, of which bisphosphonates (BPs) seem to have the maximum benefit in reducing fracture rate and improving bone density. Zolendronic acid is a newer BP tried for several bone diseases, mainly in adults. The objective of our analysis was to study the response to zolendronic acid in children with type III OI. The case records of subjects with type III OI receiving zolendronic acid in the past 3 years between February 2006 and March 2009 were analyzed. Relevant details were recorded on a predesigned chart. Subjective improvement, reduction in number of fractures, and the DEXA scan Z-score were used to judge improvement. Five OI type III cases were followed up in the Genetic clinic. Presentation was from neonatal period to 7 years of age; M:F ratio was 3:2. Average duration of therapy given was 20.4 months. Improvement was noted in all patients, in the form of reduction in frequency of fractures (P = 0.002) and increase in bone density on DEXA scan (P = 0.01). Side effects noted were flu-like symptoms and myalgia. No clinical problems due to hypocalcemia were noted in any of the patients. Thus, zolendronic acid is seen as a safe and effective BP in type III OI children. The exact dose for optimal benefit is yet to be determined. The long-term effects of newer BPs need further long-term trials.

A newborn with acanthosis nigricans: can it be Crouzon syndrome with acanthosis nigricans?

Crouzon syndrome is a craniosynostosis syndrome, characterized by cloverleaf skull, hypertelorism, exophthalmos, external strabismus, parrot-beaked nose, short upper lip, hypoplastic maxilla, and mandibular prognathism. The 5% of individuals with Crouzon syndrome who have pigmentary changes in the skin are said to have Crouzon syndrome with acanthosis nigricans (CAN). Choanal atresia, hydrocephalus and the cranial features of Crouzon syndrome should suggest the diagnosis of CAN even before acanthosis appears. We present a 10-hour-old newborn who presented with bilateral choanal atresia, craniosynostosis and acanthosis nigricans. Molecular tests identified the FGFR3 Ala391Glu substitution confirming the diagnosis of CAN. Of the 35 cases of CAN reported in literature till date, only one child had acanthosis nigricans at birth. This is the first case from India to have been reported with this mutation.

Seven novel genetic variants in a North Indian cohort with classical homocystinuria.

Classical homocystinuria is the most common cause of isolated homocystinuria. The variants of the CBS gene remain unidentified in Indian children with this disorder. Based on the hallmark clinical features, family history, and/or biochemical clues for classical homocystinuria, 16 children below the age of 18 years were evaluated by Sanger sequencing of the coding exons of CBS gene with flanking intronic regions. The common C677T variant of the MTHFR gene was also screened by restriction fragment length polymorphism. Fifteen children were clinically suspected of having classical homocystinuria and one asymptomatic child with positive family history. Only seven children had biochemical features of classical homocystinuria. Sanger sequencing of the CBS gene confirmed 15 different pathogenic or likely pathogenic variants in 14 cases. Of these, seven variants were novel (three frameshift deletions, two nonsense, one missense, one splice site variant) and were predicted to be deleterious by Mutation Taster software. Seven cases were homozygous, another six were compound heterozygous, and one case was single heterozygous in the study. None of the three most frequent mutations reported worldwide viz., I278T, G307S, and IVS 11-2A>C were found in our cohort. No variants were detected in the exons 2, 8, 12, and 14 as compared to reported literature. Eleven out of 15 variants were associated with the conserved catalytic domain of the CBS polypeptide. The MTHFR polymorphism C677T was observed in heterozygous state in six cases. Our study reports the detailed genotype and seven novel variants in the CBS gene, causing classical homocystinuria in Indian children. The genetic analysis will help to offer accurate genetic counseling, prenatal diagnosis, and development of mutation-based novel therapeutic strategies.

Spontaneous hematomyelia in a child with hemophilia A: a case report.

Hemorrhagic complications in patients with hemophilia have been occasionally reported in the spinal column and the spinal cord. Treatment is based on prompt replacement therapy as the occurrence and development of neurologic dysfunction are related to the length of time between the onset of symptoms and the factor replacement. We report case of a 7-year-old hemophilic boy who presented with flaccid paraparesis resulting from thoracic hematomyelia. The patient showed gradual improvement on medical management with cryoprecipitate infusions. This case calls attention to the need for prompt diagnosis of rarely reported spinal hematomyelia based on clinical manifestations and radiologic features and highlights its management options in patients with hemophilia.

Issues in counseling for Down syndrome.

We studied the background information, concerns and specific queries of thirty-four families of children with Down syndrome. Majority of the parents were aware that their child has Down syndrome and has or will have mental retardation. However, most of the families were ignorant about the lack of curative treatment, chromosomal nature of the disorder and prenatal screening and testing options.

Autosomal Recessive Cutis Laxa Type II: Report of Novel Mutation in a Child.

Autosomal recessive cutis laxa type-II (ARCLII) is a spectrum of clinical disorders with prenatal and postnatal growth retardation, cutis laxa, dysmorphism, and skeletal abnormalities. We report the case of a 14-month-old boy with developmental delay, hypotonia, dysmorphism, and loose skin. A novel homozygous variant was observed in ATP6VOA2 gene. Clinical spectrum of ARCLII is highly heterogeneous and molecular analysis should be done to confirm the diagnosis.

Concentrations of leptin, adiponectin and other metabolic parameters in non-obese children with Down syndrome.

BACKGROUND: Recent data indicates that adults with Down syndrome (DS) are at increased risk for cardiovascular disease (CVD) that significantly contributes to their morbidity and mortality. Although identification of cardiometabolic risk factors during childhood is desirable to design preventive interventions, the data on such risk factors in children with DS is scarce. The aim of this study was to study the cardiometabolic risk factors such as insulin resistance (IR), leptin and adiponectin concentrations, lipid abnormalities and leptin resistance in non-obese children with DS. METHODS: This cross-sectional case control study included karyotype confirmed trisomy-21 DS children aged 2-12 years and their matched healthy controls. After detailed anthropometry, weight, height and body mass index (BMI) standard deviation scores (SDSs) were calculated with reference data. Laboratory evaluation included determination of fasting lipid parameters, insulin, glucose, leptin and adiponectin concentrations. The homeostasis model assessment method (HOMA-IR) was used to assess IR and the ratio of leptin to BMI was used as an index of leptin resistance. RESULTS: Seventy-seven children (39 with DS and 38 controls) comprised the study cohort. The anthropometric parameters were similar in the two groups. Children with DS showed significantly higher mean leptin concentrations (2.098±1.68 ng/mL vs. 1.44±0.52 ng/mL, p-value: 0.00) and higher indices of leptin resistance (0.127±0.085 vs. 0.09±0.03, p-value: 0.001) as compared to controls. Fasting adiponectin concentrations were lower (20.64±19.87 ng/mL vs. 32.58±34.25 ng/mL, p-value: 0.21) and fasting glucose higher (89.25±8.12 mg/dL vs. 85.71±5.52 mg/dL, p-value: 0.06) in the DS group as compared to the controls but the differences did not reach statistical significance. The concentrations of insulin, various lipid parameters and calculated HOMA-IR values were similar in the two groups. In the DS group, five children were identified to have high (>75th centile) leptin levels and four as impaired fasting glucose as compared to none in the controls. CONCLUSIONS: Alterations of several cardiometabolic risk factors, in particular, leptin concentrations and leptin resistance are present in children with DS. The presence of hyperleptinemia without hyperinsulinemia suggests a probable inherent genetic basis for increased leptin resistance in patients with DS. There is a need for larger studies to further understand increased leptin resistance in DS that may contribute to increased CVD related morbidity and mortality in these patients.

Recurrent and novel GLB1 mutations in India.

GM1 gangliosidosis is a lysosomal storage disorder caused by mutations in the GLB1 gene, leading to the deficiency of the enzyme ß-d-galactosidase. In this study, we report molecular findings in 50 Asian Indian families with GM1 gangliosidosis. We sequenced all the exons and flanking intronic sequences of GLB1 gene. We identified 33 different mutations (20 novel and 13 previously reported). The novel mutations include 12 missense (p.M1?, p.E129Q, p.G134R, p.L236P, p.G262E, p.L297F, p.Y331C, p.G414V, p.K493N, p.L514P, p.P597L, p.T600I), four splicing (c.246-2A>G, c.397-2A>G, c.552+1G>T, c.956-2A>G), three indels (p.R22Qfs*8, p.L24Cfs*47, p.I489Qfs*4) and one nonsense mutation (p.Q452*). Most common mutations identified in this study were c.75+2InsT (14%) and p.L337P (10%). Known mutations accounted for 67% of allele frequency in our cohort of patients, suggesting that these mutations in GLB1 are recurrent across different populations. Twenty three mutations were localized in the TIM barrel domain, ß-domain 1 and ß-domain 2. In silico sequence and structure analysis of GLB1 reveal that all the novel mutations affect the function and structure of the protein. We hereby report on the largest series of patients with GM1 gangliosidosis and the first from India.

Diabetes mellitus in an infant.

Onset of diabetes in the first year of life is uncommon, most cases being those of transient diabetes of the newborn. We report the case of a child who presented at 10 weeks of age with diabetic keto-acidosis, and continues to be insulin dependent at 18 months.

Hypophosphatemic rickets caused by a novel PHEX gene mutation in an Indian girl.

We report a girl who presented with clinical and biochemical features of hypophosphatemic rickets. Mutational analysis detected a heterozygous nonsynonymous sequence variation in exon 11 of the PHEX gene (NM_000444.4:c.1216T>C, NP_000435.3:p.Cys406Arg). This previously undescribed PHEX mutation is probably the cause of renal phosphate wasting in our patient that resulted in rickets.