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Background: Thyroid Disorders represent the most common endocrinopathy in childhood and a preventable cause of growth delay and mental retardation. Clinical manifestations of hypothyroidism are highly variable depending upon etiology, duration, age and severity. True incidence of congenital hypothyroidism in Pakistan is unknown due to lack of community surveys and long awaited national newborn screening program for hypothyroidism. Objective: We aimed to determine the various etiological factors involved in the development of congenital hypothyroidism (CH) in cases coming to a tertiary care center. We also aimed to study the varied clinical presentation of congenitally hypothyroid cases to appreciate early detection and prompt diagnosis. Methodology: This was a descriptive cross-sectional study conducted in the Endocrine Section of Department of Pediatrics, Mayo Hospital, King Edward Medical University (KEMU), Lahore, from July 2012 to January 2019. A predesigned proforma was used to record clinical and biochemical parameters of the Patients. The diagnosis of CH was based on clinical, radiological, and biochemical features. Results: Out of 198 cases of permanent CH, 58.6% (116/198) were female. Among study patients, 33% (66/198) were under the age of 3 years, 32.2% (64/198) aged 3-11 months and 19.7% (39/198) between 1 - 3 years of age. The common clinical features at presentation were constipation 56.6%, unusual facies 53%, learning difficulties 42.4%, mental retardation 39.4%, short stature 38% and goiter 25.8% patients. Regarding aetiology, hormonal dysgenesis (56.5%) and iodine deficiency (26.6%) were found to be the common underlying factors. The association between age at diagnosis with various variables was computed using the Pearson chi-square test. Pvalue less than 0.05 was taken as statistically significant. Conclusion: The high prevalence of iodine deficiency among Patients of CH points towards variable aetiology and importance in community health. The study also emphasizes the need to explore clinical features at different age groups, which help in establishing early diagnosis of CH in the absence of national neonatal screening programs in Pakistan. [ABSTRACT FROM AUTHOR]

Monogenic forms of obesity have been identified in ≤10% of severely obese European patients. However, the overall spectrum of deleterious variants (point mutations and structural variants) responsible for childhood severe obesity remains elusive. In this study, we genetically screened 225 severely obese children from consanguineous Pakistani families through a combination of techniques, including an in-house-developed augmented whole-exome sequencing method (CoDE-seq) that enables simultaneous detection of whole-exome copy number variations (CNVs) and point mutations in coding regions. We identified 110 (49%) probands carrying 55 different pathogenic point mutations and CNVs in 13 genes/loci responsible for nonsyndromic and syndromic monofactorial obesity. CoDE-seq also identified 28 rare or novel CNVs associated with intellectual disability in 22 additional obese subjects (10%). Additionally, we highlight variants in candidate genes for obesity warranting further investigation. Altogether, 59% of cases in the studied cohort are likely to have a discrete genetic cause, with 13% of these as a result of CNVs, demonstrating a remarkably higher prevalence of monofactorial obesity than hitherto reported and a plausible overlapping of obesity and intellectual disabilities in several cases. Finally, inbred populations with a high prevalence of obesity provide unique, genetically enriched material in the quest of new genes/variants influencing energy balance. [ABSTRACT FROM AUTHOR]

Objective Single gene mutations leading to severe obesity have so far been identified in 3-5% cases in European populations. However, prevalence of these pathogenic mutations has not systematically been examined in specific consanguineous populations. Here we describe the incidence of obesity-associated mutations through a step-wise sequence analysis, in a cohort of 73 Pakistani children with severe obesity from consanguineous families. Methods Initially, all subjects were screened for mutations in coding regions of leptin ( LEP) and melanocortin 4 receptor ( MC4R) genes by direct sequencing. Subjects negative for mutation in these genes were screened using microdroplet PCR enrichment and NGS. Genomic structural variation was assessed by genotyping. Serum leptin, insulin, and cortisol were determined by ELISA. Results Among 73 children with severe obesity (BMI SDS > 3.0), we identified 22 probands and 5 relatives, carrying 10 different loss-of-function homozygous mutations in LEP, leptin receptor ( LEPR), and MC4R genes, including 4 novel variants. Hypercortisolemia was significantly emphasized in LEP mutation carriers. Conclusions The prevalence of pathogenic mutations in genes known to directly influence leptin-melanocortin signaling is 30% in our cohort. The results of this study emphasize the desirability of undertaking systematic and in-depth genetic analysis of cases with severe obesity in specific consanguineous populations. [ABSTRACT FROM AUTHOR]

Objective Mutations in leptin receptor gene ( LEPR) result in early onset extreme adiposity. However, their prevalence in different populations is not known. Indeed, LEPR screening by gold standard Sanger sequencing has been limited by its large size and the cost. One-step PCR-based targeted enrichment could be an option for rapid and cost effective molecular diagnosis of monogenic forms of obesity. Methods The study is based on 39 unrelated severely obese Pakistani children, previously shown to be negative for leptin ( LEP) and melanocortin 4 receptor ( MC4R) gene mutations, from an initial cohort of 62 probands. Patient samples were analyzed by microdroplet PCR-enrichment (RainDance technologies) targeting coding exons of 26 obesity-associated genes combined with next generation sequencing. Hormone levels were analyzed by ELISA. Results The analysis revealed two novel homozygous LEPR mutations, an essential splice site mutation in exon 15 (c.2396-1 G>T), and a nonsense mutation in exon 10 (c.1675 G>A). Both probands had high leptin levels and were phenotypically indistinguishable from age-matched leptin-deficient subjects from the same population. Conclusions The two subjects carrying homozygous LEPR mutations, reported here for the first time in the Pakistani population, constitute 3% of the whole cohort of severely obese children (compared to 17% for LEP and 3% for MC4R). [ABSTRACT FROM AUTHOR]

Abstract: Recessive or co-dominant single-gene mutations disrupting leptin melanocortin pathway cause severe obesity and hyperphagia. Since Pakistan has a very high rate of consanguinity, therefore, a significantly higher incidence of monogenic obesity is expected in its population. We have assessed the incidence of LEP and MC4R mutations and associated hormonal profiles, in a cohort of randomly selected Pakistani children with early onset of severe obesity. Sixty two unrelated children of consanguineous parents, with a weight-for-age percentile >97 were recruited in the study. Screening for mutations in the coding regions of LEP and MC4R was performed by direct sequencing. Serum hormone concentrations were determined by immunoassay. LEP mutations were found in 16.1% of the probands. Of these, 9 probands carried the homozygous frameshift mutation, G133_VfsX14, whereas one patient had a homozygous mutation involving deletion of 3 base pairs, (I35del). In these probands, leptin levels were very low or undetectable and insulin levels were increased in 33%. Homozygous MC4R mutations, M161T and I316S, identified separately in 2 subjects (3.2%), were associated with severe obesity, hyperphagia, hyperleptinemia and hyperinsulinemia. The heterozygous M161T sibling had normal body weight and hormone levels and the parents were only mildly overweight. Based on genetic analysis of LEP and MC4R genes only, we elucidated genetic causality of severe obesity in 20% of our patients confirming high prevalence of monogenic form of obesity in this consanguineous population. Co-dominancy of MC4R is exacerbated in this group with non-penetrance of obesity in heterozygous loss-of-function MC4R mutation carriers. The sub-ethnic specificity of LEP mutation, G133_VfsX14, suggests a founder effect. [Copyright &y& Elsevier]

A correction to the article "Genetic Variants in LEP, LEPR, and MC4R Explain 30% of Severe Obesity in Children From a Consanguineous Population" appeared in the previous issue is presented.