Primary Hypothyroidism with Pituitary Hyperplasia in an Omani Girl.

Pituitary hyperplasia secondary to primary hypothyroidism (PHPH) is uncommon in children and is reversible with thyroxine therapy. We report an Omani girl who presented at the age of 13 years and 6 months with profound primary hypothyroidism due to Hashimoto's thyroiditis and secondary pituitary hyperplasia and hyperprolactinemia. Pituitary magnetic resonance imaging confirmed the presence of pituitary hyperplasia which regressed during follow-up after the administration of thyroxine therapy. The diagnosis of PHPH is very important in both children and adults in order to avoid unnecessary brain surgery or medical treatment for a presumed pituitary mass or adenoma. To our knowledge, this patient represents the first case of an Omani child presenting with PHPH.

A Unique Genotype of Pseudohypoaldosteronism Type 1b in a Highly Consanguineous Population.

CONTEXT: Pseudohypoaldosteronism (PHA) is a condition in which serum aldosterone level is normal or elevated but its action is deficient. OBJECTIVE: This study describes the molecular genetics of PHA 1b in the highly consanguineous population of 2 Arabian Gulf countries, Saudi Arabia and Oman. METHODS: This study enrolled 22 patients from 13 unrelated families (2 families with 5 patients from Oman and 11 families with 17 patients from Saudi Arabia). All of these patients had presented within the first 10 days of life with nausea and vomiting, hyponatremia, hyperkalemia, and hypotension. We isolated DNA from peripheral blood and PCR-sequenced all exons and exon-intron boundaries of SCNN1A and, if negative, SCNN1B and SCNN1G using the Dideoxy Chain termination method. RESULTS: We found a total of 8 mutations in 13 families as follows: 6 mutations in SCNN1A, 1 in SCNN1B, and 1 in SCNN1G. All of these mutations were novel except one. SCNN1A mutations were: c.1496A>G, p.Q499R (novel) in 1 patient; c.1453C>T, p.Q485X (novel) in 1 patient; c.1322_1322delA, p.N441Tfs*41 (novel) in 2 patients of 1 family; c.876 + 2 delGAGT (novel) in 3 patients of 1 family; c.203_204 delTC, p.I68Tfs*76 (a known mutation) in 8 patients of 5 families; and whole SCNN1A gene deletion (novel) in 2 patients of 2 families. In addition, a nonsense SCNN1B mutation c.1694C>A, p.S565X (novel) was found in 3 siblings from 1 Omani family, and an SCNN1G deletion mutation c.527_528 delCA, p.T176Rfs*9 (novel) in 2 siblings from another Omani family. CONCLUSION: We characterized a unique genotype of PHA 1b with several novel gene structure-disrupting mutations in SCNN1A, SCNN1B, and SCNN1G in a highly consanguineous population.

Case Report: Investigation and molecular genetic diagnosis of familial hypomagnesaemia.

Genetic mutations causing familial hypomagnesaemia syndromes are well-recognised.  Affected patients can present with severe symptoms of hypomagnesaemia, such as seizures or cardiac arrhythmia.  We report an affected child, from a consanguineous family, who presented in the first weeks of life with seizures secondary to hypomagnesaemia, without other associated clinical features.  We performed whole exome sequencing in the affected child and segregation analysis within the family, which revealed a novel homozygous missense mutation in TRPM6, which was confirmed as a heterozygous allele in both parents and two younger siblings who had transient hypomagnesaemia. Using in silico modelling, we provide evidence that the missense variant p.(K1098E) in TRPM6 is pathogenic, as it disrupts stabilising TRP domain interactions. Management of familial hypomagnesaemia relies on prompt recognition, early magnesium replacement and lifelong monitoring.

Higher serum alkaline phosphatase activity in infants born to vitamin D-deficient mothers.

Our research shows that the newborns of vitamin D-deficient mothers have higher serum alkaline phosphatase (ALP) activity compared with those of vitamin D-non-deficient mothers, which is likely related to increased bone turnover rather than just being a marker for bone formation. This has a potential negative impact on fetal bone development and subsequent skeletal growth. PURPOSE/INTRODUCTION: Low maternal serum 25-hydroxy vitamin D (25(OH)D) level during pregnancy contributes to vitamin D deficiency in infants at birth, which is associated with multiple potential adverse effects on fetal skeletal mineralization and growth. We studied the relationship between maternal 25(OH)D level and newborn serum alkaline phosphatase activity (ALP) at term. METHODS: In this prospective cross-sectional hospital-based study, venous blood samples of healthy pregnant mothers were drawn to measure 25(OH)D levels within 6 h of delivery. Cord blood samples were examined for calcium, phosphorus levels, and ALP activity immediately after birth. In addition, we also recorded the newborns' anthropometric measurements. RESULTS: Seventy-two percent (n = 108/150) of mothers in our study were vitamin D-deficient (serum 25(OH)2D < 25 nmol/l). In a multivariate logistic regression model, young maternal age (odds ratio (OR) = 0.94, 95% CI 0.88-0.99, p = 0.04) and increased weight (OR = 1.03, 95% CI 1.01-1.07, p = 0.02) as well as decreased milk intake (OR = 0.31, 95% CI 0.13-0.74, p = 0.009) were all significantly associated with maternal vitamin D deficiency. ALP activity was significantly higher in newborns of vitamin D-deficient compared with vitamin D-non-deficient mothers (median = 176 (IQR = 139-221) and 156 (IQR = 132-182), respectively, p = 0.04). A significant inverse correlation (Pearson's coefficient = - 0.18, p = 0.03) was observed between maternal 25(OH)D levels and babies' ALP activities. This association persisted in a multivariate logistic regression model (OR = 3.46, 95% CI 1.18-10.18, p = 0.024). CONCLUSIONS: Our findings indicate that newborns of vitamin D-deficient mothers have higher serum ALP activity than those of non-deficient mothers, which might be related to increased bone turnover rather than just being a marker for bone formation. This could have a potential negative impact on fetal bone development and subsequent skeletal growth.

Clinical characteristics and phenotype-genotype review of 25 Omani children with congenital hyperinsulinism in infancy. A one-decade single-center experience.

OBJECTIVES: To report the genotype-phenotype characteristics, demographic features and clinical outcome of Omani patients with congenital hyperinsulinism (CHI). Methods: We retrospectively analyzed the clinical, biochemical, genotypical, phenotypical characteristics and outcomes of  children with CHI who were presented to the pediatric endocrine team in the Royal Hospital, Muscat, Oman between January 2007 and December 2016. Results: Analysis of 25 patients with CHI genetically revealed homozygous mutation in ABCC8 in 23 (92%) patients and 2 patients (8%) with compound heterozygous mutation in ABCC8. Fifteen (60%) patients underwent subtotal pancreatectomy as medical therapy failed and 2 (8%) patients showed response to medical therapy. Three patients expired during the neonatal period, 2 had cardiomyopathy and sepsis, and one had sepsis and severe metabolic acidosis. Out of the 15 patients who underwent pancreatectomy, 6 developed diabetes mellitus, 6 continued to have hypoglycemia and required medical therapy and one had pancreatic exocrine dysfunction post-pancreatectomy, following up with gastroenterology clinic and was placed on pancreatic enzyme supplements, while 2 patients continued to have hypoglycemia and both had abdominal MRI and 18-F-fluoro-L-DOPA positron emission tomography scan (PET-scan), that showed  persistent of the disease and started on medical therapy. Conclusion:  Mutation in ABCC8 is the most common cause of CHI and reflects the early age of presentation. There is a need for early diagnosis and appropriate therapeutic strategy.

Testosterone- and Cortisol-secreting Oncocytic Adrenocortical Adenoma in the Pediatric Age-group.

Oncocytic tumors are epithelial neoplasms that occur in various organs, including adrenal glands. Oncocytic adrenocortical adenomas and carcinomas are uncommon but well-known pathological entities in adults. However, generally oncocytic tumors, particularly in the adrenal glands, are very rare in the pediatric age-group. Most oncocytic adrenal tumors are not functional. We present a rare case of right-sided, functional oncocytic adrenocortical adenoma in a 5-year-old boy, who presented with clinical manifestations of precocious puberty and Cushing syndrome. Laparoscopic adrenalectomy showed a well-defined mass weighing 8.4 g and measuring 3 cm in maximum dimension. Histological examination demonstrated no features suggestive of aggressive biological behavior. The patient showed no evidence of recurrent or metastatic disease and continued to have normal serum hormonal levels 28 months following the surgery. In this report, we discuss the clinicopathological characteristics of this rare pathological entity and briefly review the literature on functional oncocytic adrenal tumors in the pediatric population.

Genetic mutations associated with neonatal diabetes mellitus in Omani patients.

BACKGROUND: Neonatal diabetes mellitus (NDM) is a rare disorder worldwide where diabetes is diagnosed in the first 6 months of life. However, Oman has a relatively high incidence of NDM. METHODS: In this study, we investigated the genetic etiologies underlying NDM and their prevalence in Oman. We collected a cohort of 24 NDM patients, with and without genetic diagnosis, referred to our center from 2007 to 2015. All patients without a genetic diagnosis were tested for mutations in 23 NDM-associated genes using a custom-targeted next-generation sequencing (NGS) panel and methylation analysis of the 6q24 locus. RESULTS: A genetic abnormality was detected in 15/24 (62.5%) of our Omani NDM patients. We report the detection of 6q24 methylation abnormalities and KCNJ11 mutations for the first time in Omani NDM patients. Unlike Western populations where NDM is predominantly due to mutations in the KCNJ11, ABCC8 and INS genes, NDM due to homozygous GCK gene mutations were most prevalent in Oman, having been observed in seven out of 15 NDM patients in whom we established the genetic etiology. This reflects the high degree of consanguinity which makes recessive conditions more likely. CONCLUSIONS: The results of this study are likely to impact any future strategy to introduce genetic testing for NDM disorders within the national healthcare system in Oman.

Clinical, genetic, and structural basis of apparent mineralocorticoid excess due to 11ß-hydroxysteroid dehydrogenase type 2 deficiency.

Mutations in 11ß-hydroxysteroid dehydrogenase type 2 gene (HSD11B2) cause an extraordinarily rare autosomal recessive disorder, apparent mineralocorticoid excess (AME). AME is a form of low renin hypertension that is potentially fatal if untreated. Mutations in the HSD11B2 gene result either in severe AME or a milder phenotype (type 2 AME). To date, ∼40 causative mutations have been identified. As part of the International Consortium for Rare Steroid Disorders, we have diagnosed and followed the largest single worldwide cohort of 36 AME patients. Here, we present the genotype and clinical phenotype of these patients, prominently from consanguineous marriages in the Middle East, who display profound hypertension and hypokalemic alkalosis. To correlate mutations with phenotypic severity, we constructed a computational model of the HSD11B2 protein. Having used a similar strategy for the in silico evaluation of 150 mutations of CYP21A2, the disease-causing gene in congenital adrenal hyperplasia, we now provide a full structural explanation for the clinical severity of AME resulting from each known HSD11B2 missense mutation. We find that mutations that allow the formation of an inactive dimer, alter substrate/coenzyme binding, or impair structural stability of HSD11B2 yield severe AME. In contrast, mutations that cause an indirect disruption of substrate binding or mildly alter intramolecular interactions result in type 2 AME. A simple in silico evaluation of novel missense mutations could help predict the often-diverse phenotypes of an extremely rare monogenic disorder.