Corticosterone Methyl Oxidase Type 1 (CMO1) Deficiency Due to CYP11B2 Mutation: Two Case Reports.

Aldosterone synthase deficiency (ASD) is a rare autosomal recessive condition due to an inactivating mutation in CYP11B2. There are two types of ASD depending upon level of defect in aldosterone synthesis, corticosterone methyl oxidase type 1 (CMO 1) and type 2 (CMO 2) deficiency. We are reporting two cases of CMO 1 deficiency presented with failure to thrive. Both cases were born to consanguineous parents and presented at around 17 months and 15 months with complaints of repeated vomiting and failure to thrive. They were found to have persistent hyponatremia, hyperkalemia, low aldosterone level, raised renin levels, normal cortisol and normal 17 hydroxyprogesterone level, suggesting the diagnosis of isolated aldosterone deficiency. Whole exome sequencing revealed that Case 1 is carrying a novel homozygous mutation in CYP11B2, c.1391_1393dup p.(Leu464dup) and Case 2 has a homozygous pathogenic variant in CYP11B2, c.922T>C p.(Ser308Pro), confirming the diagnosis of CMO 1 deficiency in both cases. After initial stabilization, both cases were started on oral fludrocortisone. They responded well and showed a good catch-up in growth and development. Aldosterone synthase deficiency is a rare condition, but it shall be suspected in infants presented with failure to thrive, hyponatremia and hyperkalemia without pigmentation and virilization.

Clinical spectrum and diagnostic challenges of vitamin D dependent rickets type 1A (VDDR1A) caused by CYP27B1 mutation in resource limited countries.

OBJECTIVES: Vitamin D dependent rickets type 1A (VDDR1A) is a rare autosomal recessive condition due to inactivating mutation of CYP27B1. It mimics clinically, biochemically and rediologically to nutritional and hypophosphatemic rickets. In developing countries like Pakistan, VDDR1A is often misdiagnosed as nutritional rickets or hypophosphatemic rickets due lack of free access to 1,25 (OH) 2 D level and genetic testing. This study was aimed to determine the clinical spectrum and diagnostic challenges of VDDR1A due to CYP27B1 mutation in developing countries. METHODS: Retrospective review of all cases of VDDR1A due to CYP27B1 mutation over a period of two years presenting in the Pediatric Endocrine clinic of Hameed Latif Hospital, Lahore, Pakistan. RESULTS: Six cases of VDDR1A (4 males) were identified. Mean age of clinical manifestation was 14 (9-24) months. Mean age of presentation to endocrine department was 5.5 (1.5-11.8) years. Growth failure and bony deformities were the most common presentation (n=6), followed by repeated diarrheas and abdominal distension (n=3) and recurrent fractures (n=1). All cases shared same biochemical profile of low/normal calcium, hypophosphatemia, raised alkaline phosphatase, raised PTH, normal/high 25(OH)D and tubular reabsorption of phosphate (TRP) <85%. Patients treated with calcitriol showed rapid healing as compared to those treated with 1-alfacalcidol. CONCLUSIONS: We should have a high index of suspicion of VDDR1A in rickets not responding to cholecalciferol therapy.

Spectrum of neuro-developmental disorders in children with congenital hyperinsulinism due to activating mutations in GLUD1.

Background: Hyperinsulinism/hyperammonemia (HI/HA) syndrome is the second most common type of congenital hyperinsulinism caused by an activating GLUD1 mutation. Objective: The aim of this study was to determine the clinical profile and long-term neurological outcomes in children with HI/HA syndrome. Method: This study is a retrospective review of patients with GLUD1 mutation, treated at two centers in the UK and Russia, over a 15-year period. Different risk factors for neuro-developmental disorders were analysed by Mann-Whitney U test and Fisher's exact P test. Results: We identified 25 cases with GLUD1 mutations (12 males). Median age of presentation was 7 months (12 h-18 months). Hypoglycaemic seizures were the presenting feature in 24 (96%) cases. Twenty four cases responded to diazoxide and protein restriction whilst one patient underwent partial pancreatectomy. In total, 13 cases (52%) developed neurodevelopmental manifestations. Epilepsy (n = 9/25, 36%), learning difficulties (n = 8/25, 32%) and speech delay (n = 8/25, 32%) were the most common neurological manifestation. Median age of presentation for epilepsy was 12 months with generalised tonic-clonic seizures being the most common (n = 4/9, 44.4%) followed by absence seizures (n = 3/9, 33.3%). Early age of presentation (P = 0.02), diazoxide dose (P = 0.04) and a mutation in exon 11 or 12 (P = 0.01) were associated with neurological disorder. Conclusion: HI/HA syndrome is associated with wide spectrum of neurological disorders. These neurological manifestations were more frequent in cases with mutations affecting the GTP-binding site of GLUD1 in our cohort.

Management challenges of Rabson Mendenhall syndrome in a resource limited country: a case report.

OBJECTIVES: Rabson Mendenhall syndrome  (RMS) is a rare form of insulin resistance syndrome caused by insulin receptor mutation. In term of severity, it lies at an intermediate point on spectrum of insulin resistance with Donohue syndrome flanking the severe and Type A insulin resistance at the mild end. We are reporting a 3.5-month-old boy with RMS along with its management challenges in a resource limited country. CASE PRESENTATION: An infant presented at 3.5-month of an age with failure to thrive and fluctuating blood glucose level (hyperglycaemia and hypoglycaemia) along with clinical features of insulin resistance. He was found to have raised HbA1C, high insulin and C peptide level and a homozygous mutation in INSR gene c.1049C>T, (p.Ser350 Leu) confirming the diagnosis of RMS. He was managed with long-acting insulin (Detemir) along with frequent feeding. CONCLUSIONS: RMS in resource limited countries could be managed with frequent feeding along with insulin. Early diagnosis and management can improve long term outcome.

Precocious puberty: The clinical profile and the etiological classification of children presented at a tertiary care children's hospital.

Objectives: To determine the clinical spectrum and underlying etiologies of children presented with precocious puberty at The Children's Hospital &The Institute of Child health, Lahore. Methods: It is a retrospective review of all the children presented with precocious puberty over one year, from January 2015 to December 2015; at the department of Paediatric Endocrinology & Diabetes, The Children's Hospital & The Institute of Child Health, Lahore. Results: Total 43 cases of precocious puberty (PP), with 26 females were reported in one year. Central precocious puberty (CPP) constituted 55.8% (24/43) and was found to be more prevalent in female (22/24). In 20/24 cases (83.3%) of central precocious puberty underlying etiology was idiopathic. Peripheral precocious puberty was found in 19/43 cases (44.1%) with male predominance (15/19). Congenital adrenal hyperplasia was the most frequent (12/19) underlying cause of peripheral precocious puberty in our cohort. Conclusion: Precocious puberty could be a manifestation of underlying serious medical condition. It should be thoroughly evaluated with the aim to diagnose the underlying pathology and to treat them promptly.

Diazoxide-responsive hyperinsulinaemic hypoglycaemia in tyrosinaemia type 1.

SUMMARY: Tyrosinaemia type 1 (TT1) is a rare inherited disorder of amino acid metabolism typically presenting with liver failure and renal tubular dysfunction. We describe three individuals with TT1 and transient hyperinsulinaemic hypoglycaemia (HH). Two siblings with TT1 and acute liver dysfunction were diagnosed with hyperinsulinaemic hypoglycaemia in the neonatal period. Both siblings were successfully treated with diazoxide/chlorthiazide and treatment was gradually weaned and stopped after 8 and 6 months of age respectively. The third patient presented with a neonatal liver failure with mild cholestasis, coagulopathy, fundus haemorrhages, vitamin A and E deficiency and hyperinsulinaemic hypoglycaemia. He maintained euglycaemia on high dose diazoxide (5-12 mg/kg/day) but developed pulmonary hypertension at 12 weeks of age. After discontinuation of diazoxide, he continued maintaining his blood glucose (BG) within the normal range. Although histological abnormalities of the pancreas including beta-cell hyperplasia are well documented, the exact mechanism of excessive insulin secretion in TT1 is not well understood. It may be related to the accumulation of toxic metabolites in the target organs including pancreas. Therefore, in patients with TT1 and persistent hypoglycaemia beyond the recovery of the acute liver failure, it is important to exclude hyperinsulinism which is usually transient and can be successfully treated with diazoxide and chlorothiazide. Further studies are required to determine which factors contribute to excessive insulin secretion in patients with TT1. LEARNING POINTS: Every child with TT1 should be monitored for signs and symptoms of hypoglycaemia and screened for HH at the time of real hypoglycaemia. If hypoglycaemic episodes persist even after improvement of liver function, hyperinsulinism should be suspected. Treatment with diazoxide is effective, however, children need to be monitored closely for possible side effects. The pathophysiological mechanism of hyperinsulinism in children with TT1 is not elucidated yet and further studies are required to determine which factors contribute to excessive insulin secretion in patients with TT1.

Diazoxide-induced pulmonary hypertension in hyperinsulinaemic hypoglycaemia: Recommendations from a multicentre study in the United Kingdom.

OBJECTIVE: Diazoxide is first-line treatment for hyperinsulinaemic hypoglycaemia (HH) but diazoxide-induced pulmonary hypertension (PH) can occur. We aim to characterize the incidence and risk factors of diazoxide-induced PH in a large HH cohort to provide recommendations for anticipating and preventing PH in diazoxide-treated patients with HH. DESIGN AND PATIENTS: Retrospective cohort study involving four UK regional HH centres; review of case notes of HH patients on diazoxide. MEASUREMENTS: The diagnosis of PH was based on clinical and echocardiography evidence. Patient and treatment-related risk factors were analysed for association. RESULTS: Thirteen (6 men) of 177 HH diazoxide-treated patients developed PH, an incidence of 7%. In the PH group, HH was diagnosed at median (range) of 9 (1,180) days, with diazoxide commenced 4 (0,76) days from diagnosis and reaching a maximum dose of 7 (2.5,20) mg/kg/d. The majority (8 of 13 patients) developed PH within 2 weeks of diazoxide. Complete diazoxide withdrawal, but not dose reduction, led to PH resolution at 41 (3,959) days. In three patients, PH continued beyond 12 months. Risk factors for the development of PH included the presence of congenital heart disease (CHD) (P = .008), and total fluid volume exceeding 130 mL/kg/d in the immediate 24 hours preceding diazoxide (P = .019). CONCLUSION: Pulmonary hypertension can occur in 7% of diazoxide-treated HH patients. Risk factors include the presence of congenital heart disease and fluid overload. Recommendations include echocardiography and fluid restriction to 130 mL/kg/d prior to diazoxide treatment and immediate discontinuation of diazoxide if PH develops.

Pathogenesis of Growth Failure in Rasopathies.

The RASopathies are a group of developmental genetic syndromes that are caused by germline mutations in genes encoding proteins of the Ras-Mitogen-Activated Protein kinase (RAS-MAPK) pathway. RASopathies include Noonan Syndrome (NS), Neurofibromatosis Type 1 (NF1), Noonan syndrome with multiple lentigines (NSML/LEOPARD), Costello syndrome (CS), Cardio-facio-cutaneous syndrome (CFC), capillary malformation-arteriovenous malformation syndrome (CM-AVM) and Legius Syndrome. These syndromes have many overlapping features; however, the most persistent feature common to all is the postnatal growth failure. The mechanism of growth failure in Rasopathies is highly complex and there are many proposed hypotheses including partial growth hormone insensitivity, growth hormone deficiency, neurosecretory dysfunction of growth hormone secretion, delayed puberty, poor feeding and skeletal abnormalities. Amongst these causes, the most widely accepted is partial growth hormone insensitivity due to a post-receptor signaling defect. Growth hormone therapy seems to be effective in improving height velocity in these syndromes, although the long-term effects on final height remain unproven. However, it is important to consider the potential risk of tumors and cardiomyopathy before and during growth hormone therapy.

Ambiguous genitalia: An overview of 7 years experience at the Children's Hospital & Institute of Child Health, Lahore, Pakistan.

OBJECTIVE: To determine the classification and etiological diagnosis of children presented with ambiguous genitalia/atypical genitalia according to the newer classification system of Disorder of Sex Development (DSD). METHODS: This observational, cross-sectional study was conducted at the Department of Pediatric Endocrinology and Diabetes at The Children's Hospital &Institute of Child Health, Lahore from January, 2007 to December; 2014. Files of all the children with ambiguous genitalia were retrospectively analyzed and relevant data was retrieved. All the information was recorded on predesigned proforma and analyzed accordingly. RESULTS: A total of 300 cases of ambiguous genitalia classified according to the new DSD classification. 46, XX DSD were 54.3% (n=163), 46, XY DSD were 43.7% (n=131), sex chromosome DSD were 2% (n=6). Among 46, XX DSD cases, the most common cause was congenital adrenal hyperplasia (97%, n=158). However, in 46, XY DSD partial androgen insensitivity/5α-reductase deficiency (62%. n=81) constituted the most commonest disorder. Other causes of 46XY DSD include testosterone synthesis defect(23%), congenital adrenal hyperplasia (CAH,12%), testis regression syndrome (1.5%) and persistent mullerian duct syndrome (PMDS,1.5%). Sex chromosome disorder constituted one case of iso-chromosome X turner syndrome, mixed gonadal dysgenesis (n=3), ovotesticular DSD/chimerism (n=2). CONCLUSION: Ambiguous genitalia have varied etiologies, 46; XXDSD found being the commonest of all, showing predominance of CAH especially salt loosing type. The early detection and prompt treatment of cases of ambiguous genitalia plays a pivotal role in the management of acute life threatening condition and gender assignment.

Allgrove Syndrome: Adrenal Insufficiency with Hypertensive Encephalopathy.

Allgrove syndrome or triple-Asyndrome is a rare familial multisystem autosomal recessive disorder. It is characterised by triad of alacrima, achalasia and adrenal insufficiency due to adrenocorticotropin hormone (ACTH) resistance. If it is associated with autonomic dysfunction, it is termed as 4-Asyndrome. This syndrome is caused by a mutation in the Achalasia - Addisonism - Alacrima (AAAS) gene on chromosome 12q13 encoding the nuclear pore protein ALADIN. A5-year boy presented with history of fits and altered sensorium for one day. He also had increased pigmentation of body and persistent vomiting since six months of age. Laboratory investigations and imaging revealed alacrimia, achalasia and adrenal insufficiency due to ACTH resistance. He had episodes of hypertensive crises, for which he was thoroughly investigated and it was found to be due to autonomic instability. Based on clinical findings and investigations he was diagnosed as case of Allgrove syndrome or 4-Asyndrome with autonomic dysfunction.

Pheochromocytoma: a rare cause of childhood hypertensive encephalopathy.

Pheochromocytomas are rare neuroendocrine tumours of chromaffin tissues. They are catecholamine secreting tumours which cause severe hypertension and other systemic disturbances. Of all the causes of childhood hypertension, pheochromocytoma constitutes less than 1%. We report the case of a 12 years old child who presented with hypertensive encephalopathy, confirmed histologically to be secondary to pheochromocytoma, and cured with meticulous critical care and surgical resection.