Clinical and Genetic Profile of Children With Short Stature Presenting to a Genetic Clinic in Northern India

Objective: To define the spectrum of genetic disorders in patients with short stature visiting the genetic out-patient department in a tertiary care hospital. Methods: A chart review was done for 455 individuals (10 months-16 yrs) with short stature, who were evaluated at the genetic clinic from 1 January, 2017 upto 31 October, 2018. 226 patients who needed detailed evaluation, the spectrum of genetic diagnosis is presented. Results: Proportionate short stature was identified in 63% individuals (n=142) of which 93 (65%) were recognizable syndromes such as Turner syndrome, and William syndrome, and RASopathies. In clinically undefined syndromes (39, 27%), a diagnosis could be made by karyotype (n=3/10), chromosomal microarray (6/12) and exome sequencing (1/6). In the 84 children in the disproportionate short stature group (37%), lysosomal storage disorders (LSDs) (45%, n=38) were identified by enzyme analysis in 86.8% and skeletal dysplasias (44%, n=37) identified by skeletal survey in 89% cases. Conclusions: In undefined syndromic short stature, chromosomal microarray may be the first investigation of choice if phenotyping is not suggestive of a specific genetic syndrome. Exome sequencing can be useful in identifying newer genes among idiopathic and familial short stature cohorts.

Indian Undiagnosed Diseases Program (I-UDP) – The Unmet Need

Genomics is an integral part of many pediatric diseases spanning all sub-specialities. While many genetic disorders are diagnosed with the currently available genomic tests, there still are many patients who do not receive a definitive diagnosis. The Indian Undiagnosed Diseases Program is a multicenter effort to address these challenges and unmet needs of rare disease patients where current available genetic tests have failed to make a diagnosis. It embodies the principles of collaborative effort across multispecialty disciplines, and uses detailed phenotype. Diagnostic methods are tailored to patient specifics and the large genomic data is interrogated with precise, in-house bioinformatics pipelines using patient-specific phenotype to build the diagnostic algorithm. The inception of this research initiative in India is a step towards creating awareness and appreciation of the needs for our undiagnosed cohorts to enable appropriate management in this era of precision medicine.

Prenatal presentation of a rare genetic disorder: a clinical, autopsy and molecular correlation

Walker Warburg syndrome (WWS) lies at the severe end of the spectrum of the congenital muscular dystrophies. WWS is a congenital disorder of the O-glycosylation that disrupts in the post-translation modification of dystroglycan proteins. WWS is characterized by the involvement of the central nervous system and rarely by multisystem involvement. Next-generation sequencing discovered that multiple genes are associated with this disorder. FKTN is the rarest cause of WWS. We describe a clinical-autopsy report of a molecularly- confirmed WWS case presenting with ventriculomegaly, agenesis of the corpus callosum with a novel phenotype of Dandy-Walker malformation and unilateral multi-cystic kidney. The whole-exome sequencing confirmed a homozygous variant (c.411C>A) in the FKTN gene with a premature termination codon. This case emphasizes the importance of detailed postnatal phenotyping through an autopsy in any pregnancy with antenatally identified malformations. Obstetricians, pediatricians as well as fetal medicine experts need to counsel the parents and focus on preserving the appropriate sample for genetic testing. WWS, though rare deserves testing especially in the presence of positive family history. Dandy-Walker malformation is a novel feature and expands the phenotypic spectrum.

Diagnosis and Management of Gaucher Disease in India – Consensus Guidelines of the Gaucher Disease Task Force of the Society for Indian Academy of Medical Genetics and the Indian Academy of Pediatrics

Justification: Gaucher disease (GD) is amongst the most frequently occurring lysosomal storage disorder in all ethnicities. The clinicalmanifestations and natural history of GD is highly heterogeneous with extreme geographic and ethnic variations. The literature on GD haspaucity of information and optimal management guidelines for Indian patients.Process: Gaucher Disease Task Force was formed under the auspices of the Society for Indian Academy of Medical Genetics. Invitedexperts from various specialties formulated guidelines for the management of patients with GD. A writing committee was formed andthe draft guidelines were circulated by email to all members for comments and inputs. The guidelines were finalized in December 2016at the annual meeting of the Indian Academy of Medical Genetics.Objectives: These guidelines are intended to serve as a standard framework for treating physicians and the health care systems foroptimal management of Gaucher disease in India and to define unique needs of this patient population.Recommendations: Manifestations of GD are protean and a high index of suspicion is essential for timely diagnosis. Patients frequentlyexperience diagnostic delays during which severe irreversible complications occur. Leucocyte acid ?-glucosidase activity ismandatory for establishing the diagnosis of Gaucher disease; molecular testing can help identify patients at risk of neuronopathicdisease. Enzyme replacement therapy for type 1 and type 3 Gaucher disease is the standard of care. Best outcomes are achieved byearly initiation of therapy before onset of irreversible complications. However, in setting of progressive neurological symptoms such asseizures and or/ neuroregression, ERT is not recommended, as it cannot cross the blood brain barrier. The recommendations herein arefor diagnosis, for initiation of therapy, therapeutic goals, monitoring and follow up of patients. We highlight that prevention of recurrenceof the disease through genetic counseling and prenatal diagnosis is essential in India, due to uniformly severe phenotypes encounteredin our population

Novel mutations of the arylsulphatase B (ARSB) gene in Indian patients with mucopolysaccharidosis type VI.

Background & objectives: Mucopolysaccharidosis type VI (MPS VI) is a rare, autosomal recessive lysosomal storage disorder caused by deficient enzymatic activity of N-acetyl galactosamine-4-sulphatase resulting from mutations in the arylsulphatase B (ARSB) gene. The ARSB gene is located on chromosome 5q11-q13 and is composed of eight exons. More than hundred ARSB mutations have been reported so far, but the mutation spectrum of MPS VI in India is still unknown. Hence, the aim of the present study was to identify the mutational spectrum in patients with MPS VI in India and to study the genotype-phenotype association and functional outcomes of these mutations. Methods: Molecular characterization of the ARSB gene by Sanger sequencing was done for 15 patients (aged 15 months to 11 yr) who were enzymatically confirmed to have MPS VI. Age of onset, clinical progression and enzyme activity levels in each patient were studied to look for genotype-phenotype association. Haplotype analysis performed for unrelated patients with the recurring mutation W450C, was suggestive of a founder effect. Sequence and structural analyses of the ARSB protein using standard software were carried out to determine the impact of detected mutations on the function of the ARSB protein. Results: A total of 12 mutations were identified, of which nine were novel mutations namely, p.D53N, p.L98R, p.Y103SfsX9, p.W353X, p.H393R, p.F166fsX18, p.I220fsX5, p.W450L, and p.W450C, and three were known mutations (p.D54N, p.A237D and p.S320R). The nine novel sequence variants were confirmed not to be polymorphic variants by performing sequencing in 50 unaffected individuals from the same ethnic population. Interpretation & conclusions: Nine novel mutations were identified in MPS VI cases from India in the present study. The study also provides some insights into the genotype-phenotype association in MPS VI.

Molecular evaluation of a novel missense mutation & an insertional truncating mutation in SUMF1 gene.

Background & objectives: Multiple sulphatase deficiency (MSD) is an autosomal recessive disorder affecting the post translational activation of all enzymes of the sulphatase family. To date, approximately 30 different mutations have been identified in the causative gene, sulfatase modifying factor 1 (SUMF1). We describe here the mutation analysis of a case of MSD. Methods: The proband was a four year old boy with developmental delay followed by neuroregression. He had coarse facies, appendicular hypertonia, truncal ataxia and ichthyosis limited to both lower limbs. Radiographs showed dysostosis multiplex. Clinical suspicion of MSD was confirmed by enzyme analysis of four enzymes of the sulphatase group. Results: The patient was compound heterozygote for a c.451A>G (p.K151E) substitution in exon 3 and a single base insertion mutation (c.690_691 InsT) in exon 5 in the SUMF1 gene. The bioinformatic analysis of the missense mutation revealed no apparent effect on the overall structure. However, the mutated 151-amino acid residue was found to be adjacent to the substrate binding and the active site residues, thereby affecting the substrate binding and/or catalytic activity, resulting in almost complete loss of enzyme function. Conclusions: The two mutations identified in the present case were novel. This is perhaps the first report of an insertion mutation in SUMF1 causing premature truncation of the protein.

A familial deletion 4q syndrome: An outcome of a paracentric inversion.

Chromosome inversions are intra-chromosomal rearrangements formed when the chromosome breaks occur at two places, and in the process of repair the intervening segments are joined in an inverted or opposite manner. Inversions themselves do not appear to cause clinical anomalies, if balanced. Abnormal phenotypes can occur due to gene disruption at the point of breakage and reunion or due to duplication/deficiency recombinants formed during crossover at meiosis. We report a case with familial deletion 4q syndrome in a 1-year-old female child with dysmorphism and congenital abnormalities. The deletion was an outcome of a paracentric inversion 4q31.2q35.2. The deletion was confirmed by fluorescence in situ hybridization using telomeric DNA probes for chromosome No. 4. An attempt was made to correlate the genotype with the phenotype. The father had the same rearrangement with a milder phenotype. The recurrence risk in such cases is high.

Utility of molecular studies in incontinentia pigmenti patients.

The diagnosis of incontinentia pigmenti (IP) is fairly easy in the presence of classical features, but can be difficult in cases with partial or non-classical features, especially in the parents. The demonstration that the disease is caused by mutations in the NEMO gene, has remarkably improved genetic counselling for this disorder. We present four families of IP in whom molecular studies established an unequivocal diagnosis in the affected daughters, and showed two mothers to be carriers, thus allowing accurate genetic counselling and prenatal diagnosis.

Mutation studies in x-linked myotubular myopathy in three indian families.

Congenital myopathies are a group of genetic disorders characterized by generalised muscle hypotonia and weakness of varying severity. They are distinct entities and do not include muscular dystrophies, metabolic myopathies and mitochondrial disorders. Myotubular myopathy is a rare sub type within this group of disorders. Clinical differentiation of the various types is difficult and requires muscle biopsy with histopathological and immunohistochemical studies for specific diagnosis. Gene studies are a prerequisite for genetic counseling adn prenatal diagnosis. Here presented three cases of X-linked myotubular myopathy in three Indian families where the diagnosis was established by mutation analysis in the MTM1 gene in all, and supported his histopathology in two. All three families had history of previous male neontal deaths with similar complaints. Molecular analysis revealed hemizygous mutations in the MTM1 gene including c.1261-10A>G in case, 1, c.70C>T (R24X) in case 2, and a previously unreported mutation, c.924_926delCTT(p. F308del), in case 3. Genetic counseling was performed regarding the X-linked inheritance, their 50% risk of recurrence in boys in subsequent pregnancies, and a feasibility of prenatal diagnosis. This is the first report of cases of X-linked Myotubular myopathy from India.

Spectrum of severe skeletal dysplasias in North India.

OBJECTIVE: Severe skeletal dysplasias are a group of bone growth disorders characterized by a lethal outcome in utero or infancy. We describe our experience of the severe skeletal dysplasias diagnosed amongst fetal autopsies done at a tertiary level centre over a five year period. METHODS: We evaluated 15 cases with short limbed dwarfism, of which 13 fetuses were examined after termination of pregnancy and two were evaluated postnatally. RESULTS: Short rib dysplasia syndromes with or without polydactyly, osteogenesis imperfecta type II, thanatophoric dysplasia, campomelic dysplasia, chondrodysplasia punctata, rhizomelic type and achondrogenesis were the lethal skeletal dysplasias diagnosed. CONCLUSION: Precise identification of the tye of skeletal dysplasia is paramount for proper genetic counseling. Postnatal examination and detailed radiographic examination of the fetus especially of the pelvis, limbs, skull and spine are essential to identify the type of skeletal dysplasia.

Tyrosinemia type I--diagnostic issues and prenatal diagnosis.

A fifteen-month-old boy, born to consanguineously married couple, presented with asymptomatic hepatomegaly. Investigations revealed mildly deranged liver functions, necroinflammatory changes and cirrhosis on liver biopsy, a markedly raised alpha feto protein and tyrosine levels in plasma and a generalized aminoaciduria. His diagnosis of hereditary tyrosinemia was established on findings of raised serum and urine succinylacetone and a deficient activity of fumaryl acetoacetate hydroxylase enzyme. Prenatal diagnosis of hereditary tyrosinemia was performed in a subsequent pregnancy in this family from India.

Leber's hereditary optic neuropathy with molecular characterization in two Indian families.

PURPOSE: Leber's hereditary optic neuropathy (LHON) presents in early adulthood with painless progressive blindness of one or both eyes. Usually there is a positive family history of similar disease on the maternal side. Definitive diagnosis can be established by finding the change in the mitochondrial gene. No molecular studies have been reported from India. MATERIAL AND METHODS: Clinical, ophthalmologic and molecular studies were carried out in two patients from different families and available first degree relatives. The subjects were tested for the three common mutations seen in LHON by molecular techniques of polymerase chain reaction using mutation specific primers. RESULTS: The mutations G3460A and G11778A in the mitochondrial genes MTND1 and MTND4, known to be causative for LHON, were found in one family each. CONCLUSION: Diagnosis of LHON should be considered in familial cases and in young adults with optic atrophy. Confirmation of diagnosis should be sought by molecular gene analysis. Genetic counselling should be offered to all 'at risk' relatives of a patient harbouring the mutation.

Genetic counseling: the impact in Indian milieu.

OBJECTIVE: To assess the impact of genetic counseling in Indian milieu. METHODS: A study of 83 Indian consultants who were provided genetic counseling was carried out to understand their expectations, satisfaction with genetic counseling and its effects on reproductive decision. RESULTS: Most of the families were referred for the diagnosis and the treatment of the disorder in the proband. The consultants understood the medical facts about risk of recurrence and were satisfied with genetic counseling. There was no change in reproductive plan after genetic counseling in most of the cases. CONCLUSION: The reproductive decision was mainly correlating with the presence or absence of normal live children in the family and availability of prenatal diagnosis.

Gerodermia Osteodysplastica.

Gerodermia Osteodysplastica is a rare autosomal recessive connective tissue disorder included in the cutis laxa syndromes. Twenty five cases have been reported in the world literature to date. The authors report the first case from our country, a 13 year old female having phenotypic and radiological features suggestive of this genetic disorder.

Dysmorphology diagnosis.

A patient with multiple malformations poses a diagnostic dilemma to the pediatrician. There are thousands of malformation syndromes described and diagnosis of a syndrome appears a daunting task. An approach to diagnosis of a malformation syndrome is presented. Relevant details in the history and examination, important investigations, the process of differential diagnosis, and search engines used to aid in diagnosis of a malformation syndrome are described.

Polymorphisms in the apolipoprotein B-100 gene: association with plasma lipid concentration and coronary artery disease.

BACKGROUND: The aim of this study was to investigate the association of apolipoprotein B gene polymorphisms with coronary artery disease and lipid levels in Indians. METHODS AND RESULTS: One hundred patients of angiographically proven atherosclerotic coronary artery disease and one hundred age- and sex-matched control subjects (treadmill negative) were included in the study. Serum lipids including cholesterol, triglycerides, high-density lipoprotein, low-density lipoprotein, very low-density lipoprotein, and apolipoprotein B were analyzed. Genomic DNA was extracted and the apolipoprotein B 3' hypervariable region amplified by polymerase chain reaction. Regions carrying Xba1, EcoR1, and Msp1 restriction sites present in the apolipoprotein B gene were amplified and digested separately by the respective enzymes. Restriction fragment length polymorphism analysis showed that EcoR1 with the R+/R+ genotype was significantly more common in patients with coronary artery disease. Overall, the genotypes EcoR1+/+, Msp1+/+, Xba1+/+ and Eco R1+/+ Msp1+/-, Xba1-/- were significantly more common in patients as compared to controls (p<0.05). When gene polymorphisms were compared with lipid abnormalities, the genotypes EcoR1+/+, Xba1-/-, and Msp1+/+ were more frequent in patients with elevated apolipoprotein B and very low-density lipoprotein levels. On the other hand, these genotypes were less common in patients with increased total cholesterol and low-density lipoprotein levels. When we studied the individual alleles of the variable number of tandem repeats region, we observed that allele 34 was significantly increased in patients with coronary artery disease as compared to controls. Allele 36 was present with a frequency of 1% in controls while it was totally absent in patients. CONCLUSIONS: This study identifies the apolipoprotein B gene polymorphism associated with coronary artery disease. An association between apolipoprotein B gene polymorphisms and elevated apolipoprotein B and very low-density lipoprotein levels was observed. However, there was no positive association with other elevated lipid levels in North Indians from Uttar Pradesh.