Indian Academy of Pediatrics Revised (2021) Guidelines on Prevention and Treatment of Vitamin D Deficiency and Rickets.

JUSTIFICATION: The emerging literature on prevalence of vitamin D deficiency in India, prevention and treatment strategies of rickets, and extra-skeletal benefits of vitamin D suggest the need for revising the existing guidelines for prevention and treatment of vitamin D deficiency in India. OBJECTIVES: To review the emerging literature on vitamin D prevalence and need for universal vitamin D supplementation. To suggest optimum vitamin D therapy for treatment of asymptomatic and symptomatic vitamin D deficiency, and rickets. To evaluate the extra-skeletal health benefits of vitamin D in children. PROCESS: A National consultative committee was formed that comprised of clinicians, epidemiologists, endocrinologists, and nutritionists. The Committee conducted deliberations on different aspects of vitamin D deficiency and rickets through ten online meetings between March and September, 2021. A draft guideline was formulated, which was reviewed and approved by all Committee members. RECOMMENDATIONS: The group reiterates the serum 25-hydroxy vitamin D cutoffs proposed for vitamin D deficiency, insufficiency, and sufficiency as <12 ng/mL, 12-20 ng/mL and >20 ng/mL, respectively. Vitamin D toxicity is defined as serum 25OHD >100 ng/mL with hypercalcemia and/or hypercalciuria. Vitamin D supplementation in doses of 400 IU/day is recommended during infancy; however, the estimated average requirement in older children and adolescents (400-600 IU/day, respectively) should be met from diet and natural sources like sunlight. Rickets and vitamin D deficiency should be treated with oral cholecalciferol, preferably in a daily dosing schedule (2000 IU below 1 year of age and 3000 IU in older children) for 12 weeks. If compliance to daily dosing cannot be ensured, intermittent regimens may be prescribed for children above 6 months of age. Universal vitamin D supplementation is not recommended in childhood pneumonia, diarrhea, tuberculosis, HIV and non-infectious conditions like asthma, atopic dermatitis, and developmental disorders. Serum 25-hydroxy vitamin D level of >20 ng/mL should be maintained in children with conditions at high-risk for vitamin deficiency, like nephrotic syndrome, chronic liver disease, chronic renal failure, and intake of anticonvulsants or glucocorticoids.

Clinical application of a novel next generation sequencing assay for CYP21A2 gene in 310 cases of 21- hydroxylase congenital adrenal hyperplasia from India.

PURPOSE: Accurate diagnosis is required for management of Congenital adrenal hyperplasia (CAH). The conventional method for detection of mutations in the CYP21A2 gene is targeted capillary sequencing which is labor intensive and has limited multiplexing capability. Next generation sequencing (NGS) provides data with high sequence coverage and depth. Our objective was to develop an accurate NGS-based assay to characterize the mutation spectrum in CYP21A2 gene in Indian patients suspected to have 21-OH CAH. METHODS: Cases with 21-OH CAH from 12 endocrine units across India were studied. DNA was extracted from proband's and parent's(subset) blood. Locus-specific long-range PCR and gel electrophoresis of amplicons was followed by NGS where no visible 30 kb homozygous/whole gene deletion was observed. Orthogonal confirmation was performed by capillary sequencing (ABI 3500) and Multiplex Ligation-dependent Probe Amplification (MLPA, MRC-Holland). PCR products were purified and individual libraries were pooled and sequenced (Illumina). RESULTS: Of the 310 CAH cases, biallelic mutations (pathogenic/ likely pathogenic variants involving both CYP21A2 gene copies) were detected in 256 (82.6%), heterozygous mutations in 13 (4.2 %), and none in 41 (13.2%). Most common mutation was c.293-13A/C>G (29.03%), followed by 30 kb deletion (18.24%). Thirty samples tested orthogonally (by capillary sequencing or MLPA) showed 100% concordance with NGS assay. Nine novel variants were identified. CONCLUSIONS: We have developed and validated a comprehensive NGS-based assay for detection of variants in CYP21A2 gene in patients with 21-OH CAH. We describe CYP21A2 mutation spectrum and novel variants in a large cohort of Indian patients with CAH.

YIPF5 mutations cause neonatal diabetes and microcephaly through endoplasmic reticulum stress.

Neonatal diabetes is caused by single gene mutations reducing pancreatic ß cell number or impairing ß cell function. Understanding the genetic basis of rare diabetes subtypes highlights fundamental biological processes in ß cells. We identified 6 patients from 5 families with homozygous mutations in the YIPF5 gene, which is involved in trafficking between the endoplasmic reticulum (ER) and the Golgi. All patients had neonatal/early-onset diabetes, severe microcephaly, and epilepsy. YIPF5 is expressed during human brain development, in adult brain and pancreatic islets. We used 3 human ß cell models (YIPF5 silencing in EndoC-ßH1 cells, YIPF5 knockout and mutation knockin in embryonic stem cells, and patient-derived induced pluripotent stem cells) to investigate the mechanism through which YIPF5 loss of function affects ß cells. Loss of YIPF5 function in stem cell-derived islet cells resulted in proinsulin retention in the ER, marked ER stress, and ß cell failure. Partial YIPF5 silencing in EndoC-ßH1 cells and a patient mutation in stem cells increased the ß cell sensitivity to ER stress-induced apoptosis. We report recessive YIPF5 mutations as the genetic cause of a congenital syndrome of microcephaly, epilepsy, and neonatal/early-onset diabetes, highlighting a critical role of YIPF5 in ß cells and neurons. We believe this is the first report of mutations disrupting the ER-to-Golgi trafficking, resulting in diabetes.

Glycemic Control and Long-term Complications in Pediatric Onset Type 1 Diabetes Mellitus: A Single-center Experience from Northern India.

OBJECTIVE: To study glycemic control, mortality and long-term complications in children with type 1 diabetes (T1D). DESIGN: Cross-sectional study. SETTING: Referral centre at a government teaching hospital. PARTICIPANTS: Patients with T1D with age £18 years at onset. METHODS: We retrospectively collected demographic data from computer records from 1991 to 2015. Prospective study for outcomes was conducted between 2012 and 2016. MAIN OUTCOME MEASURES: Mortality rate, glycosylated hemoglobin (HbA1c), and microvascular complication rate. RESULTS: The proportion of T1D patients (n=512) <5 years of age at onset was 18.6% between 1995 and 2004, and 24.2% in 2005-2014 (P<0.001). Twenty eight patients had died out of 334 whose living status was known (mortality 1.1 per 100 patient-years over 2549 patient-years follow up). Median (range) HbA1c (n=257) was 8.3% (5.1-15.0%). At least one episode of severe hypoglycemia (coma/seizure/inability to assist self) had occurred in 22.8% patients over two years. Hypertension was present in 11.7% patients. Microvascular complications screen in 164 eligible patients [median (range) age 20 (8-45) y and duration of diabetes 9.1 (5-30) y] showed diabetic nephropathy in 3.0%, proliferative retinopathy in 3.6% and LDL cholesterol >100 mg/dL in 34% patients. CONCLUSIONS: The mortality rate and prevalence of hypertension were high, given the short duration of diabetes of the patients. The proportion of patients with age ≤5 years at onset of diabetes has increased at our center.

Novel mutations and spectrum of the disease of NR0B1 (DAX1)-related adrenal insufficiency in Indian children.

Background X-linked adrenal hypoplasia congenita (AHC), due to mutations in the nuclear receptor superfamily 0, group B, member 1 (NR0B1)/dosage-sensitive sex reversal, AHC, critical region on the X chromosome, gene 1 (DAX1) gene, usually presents with a salt-wasting adrenal crisis in infancy and hypogonadotropic hypogonadism (HH) in adolescents. Genetic reports in the literature from patients of diverse ethnicity are limited. We describe the atypical clinical characteristics and molecular genetic results in six Indian patients. Methods Both exons and flanking intronic sequences of the NR0B1 gene were amplified and sequenced in five patients. In the sixth patient, suspected to have a large deletion, multiplex ligation-dependent probe amplification (MLPA) and chromosomal microarray analysis were performed. Results Sequencing revealed three novel mutations: a nonsense mutation (c.776C > A), a deletion (c.298del), both causing loss of domains which are highly conserved among nuclear receptor families, and a missense mutation (c.1112T > C). In-silico analysis by structure-based protein modeling predicted a de-stabilizing effect of the novel missense mutation. Two previously reported mutations were seen in patients with atypical manifestations such as late-onset adrenal insufficiency and precocious puberty. One patient had a 7.15-Mb contiguous deletion involving the NR0B1, Duchenne muscular dystrophy (DMD), glycerol kinase (GK) and melanoma antigen, family B, 16 (MAGEB16) genes. Conclusions Our report emphasizes the wide clinical spectrum of AHC, including rare manifestations, and enumerates unique mutations in the NR0B1 gene.