Common autosomal recessive diseases in Oman derived from a hospital-based registry.

OBJECTIVES: The local frequencies of genetic disorders in Oman apart from hemoglobinopathies are largely unknown. The aim of the present study was to evaluate birth prevalence of commonly diagnosed autosomal recessive diseases and to estimate needs and priorities of genetic services. METHODS: Analysis of the years 1993-2002 using a hospital-based registry of genetic diseases was attempted. More than 3,000 records were reviewed. Only patients with definite diagnosis were included in the analysis. Genetically determined diseases occurring less frequently than 1 in 50,000 births are not included. RESULTS: A number of rare autosomal recessive diseases are found to have a prevalence at least 1 in 50,000 livebirths. CONCLUSIONS: The data suggest that genetic diseases are important as major contributors to perinatal and childhood mortality and morbidity. The need for preventive genetic service is essential for the health of the community in Oman. Autosomal recessive diseases were frequently concentrated in specific geographical areas, which can be explained by founder effect and genetic drift. However, the hospital-based registry may present incomplete information. Further prospective studies are needed to provide more detailed data.

Molecular basis for the apparent mineralocorticoid excess syndrome in the Oman population.

11beta-Hydroxysteroid dehydrogenase type 2 (11beta-HSD2) plays a crucial role in converting hormonally active cortisol to inactive cortisone, thereby conferring specificity upon the mineralocorticoid receptor (MR). Mutations in the gene encoding 11beta-HSD2 (HSD11B2) account for an inherited form of hypertension, the syndrome of "Apparent Mineralocorticoid Excess" (AME) where cortisol induces hypertension and hypokalaemia. We report five different mutations in the HSD11B2 gene in four families from Oman with a total of 9 affected children suffering from AME. Sequence data demonstrate the previously described L114Delta6nt mutation in exon 2 and new mutations in exon 3 (A221V), exon 5 (V322ins9nt) and for the first time in exon 1 (R74G and P75Delta1nt) of the HSD11B2 gene. These additional mutations provide further insight into AME and the function of the 11beta-HSD2 enzyme. The prevalence of monogenic forms of hypertension such as AME remains uncertain. However, our data suggests AME may be a relevant cause of hypertension in certain ethnic groups, such as the Oman population.

A retrospective hospital-based study on congenital hypothyroidism in the Sultanate of Oman.

A retrospective study was conducted on 45 children with congenital hypothyroidism (CH) to estimate the number of missed cases of CH among Omani children per year and compare the intellectual outcome of children diagnosed by neonatal screening (Group A) with those who were diagnosed clinically at a later age (Group B). Our results revealed 14 children in Group A, diagnosed at a mean age of 2.3 +/- 0.8 months and 31 children in Group B diagnosed at a mean age of 9.8 +/- 2.5 months. IQ assessment revealed that 67 per cent of the children in Group A had a normal IQ compared to only 15 per cent of those in Group B. The above results point to a great demand for a national screening programme in the Sultanate of Oman.

Spontaneous improvement of severe neonatal hyperparathyroidism after failed total parathyroidectomy.

We report an interesting case of severe neonatal hyperparathyroidism (SNHP) treated by sub-total parathyroidectomy, as her fourth parathyroid gland could not be identified. The clinical course changed over time to a more benign course resembling familial hypocalciuric hypercalcemia. This indicates that the natural course of SNHP is probably gradual spontaneous improvement, if patient survives the first few months of life.

Factitious hypoglycemia: a tale from the Arab world.

The mother is usually the one who narrates the patient's history to the pediatrician. Listening and eliciting the parent's story is an art. One of the essential attributes of a good pediatrician is the readiness to believe the parent's story. Mothers are good historians and careful observers. The axiom that the mother is always right is true in most instances. However, occasionally the clinician is deliberately misled by the storyteller, resulting in numerous and potentially dangerous diagnostic investigations. We describe a boy with recurrent hypoglycemic coma in whom the diagnosis of factitious hypoglycemia was delayed as it is believed to be nonexistent in our community. We emphasize that in all patients with recurrent hypoglycemia, estimation of C-peptide and insulin should be performed even when the clinical settings are not in favor of the diagnosis of Munchausen syndrome by proxy. Munchausen syndrome by proxy, hypoglycemia.

Permanent neonatal diabetes mellitus: clinical presentation and epidemiology in Oman.

AIM: To estimate the accurate incidence and prevalence of permanent neonatal diabetes mellitus, and to determine the clinical profile of this condition in the Sultanate of Oman. METHODS: All children diagnosed as having permanent neonatal diabetes mellitus between 1991 and 1995 in Oman were included in the study. RESULTS: The mean incidence was 2.2 per 100 000 live births/year and the prevalence among under 5s during 1995 was 2.0/100 000. Intrauterine growth retardation was noted in all (mean birthweight 1.86 kg), and diabetic ketoacidosis (mean plasma glucose 34.4 (SD 8.7) mmol/l, mean pH 7.17 (SD 0.09) in 80%. Hypertriglyceridaemia (mean serum triglyceride 19.06 (6.13) mmol/) was constant. No infant had clinical or immunological evidence of congenital viral infections. None had C-peptide excretion or circulating islet cell antibody during diagnosis or follow up. The other important features were parental consanguinity in all, HLA DR3/DR4 association in 80%, development of autoimmune hypothyroidism in one and observation of autoimmune disorders (insulin dependent diabetes mellitus and Hashimoto's thyroiditis) in family members. CONCLUSIONS: These findings strongly suggest an immune mediated aetiology for diabetes mellitus. The reported incidence of permanent insulin dependent neonatal diabetes mellitus in Oman is the highest in the world.

Permanent neonatal diabetes mellitus: epidemiology, mode of presentation, pathogenesis and growth.

Permanent neonatal diabetes mellitus (PNIDDM) is a rare form of IDDM with unclear etiology and pathogenesis. We determined the incidence and prevalence rates and studied the clinical and biochemical features of PNIDDM in the Sultanate of Oman. The mean incidence rate during the study period from January 1989 to December 1994 was 1.788 +/- 0.82 per 100,000 live births per year. At the end of December 1994 the prevalence rate was 2.4 per 100,000 children below the age of 5 years. They constituted 41.6% of all cases of IDDM in this age group. Diarrhoea, fever, lethargy, poor feeding and failure to thrive were the most common presenting symptoms. Dehydration and tachypnoea were the most common signs. All patients who developed IDDM during the neonatal period had intrauterine growth retardation and 4.5 presented with diabetic ketoacidosis (plasma glucose 37 +/- 9 mmol/L, pH 7.12 +/- 0.1). Hypertriglyceridemia was a constant feature (19.4 +/- 4.8 mmol/L). They were products of consanguineous marriage with significantly high prevalence of IDDM and NIDDM in their family members. None of the infants had clinical or immunological evidence of congenital viral infection. Three of the five children had HLA-DR2, the diabetes resistance alleles. C-peptide secretion was absent during and after metabolic control of hyperglycemia in all the studied infants and none had circulating islet cell antibody at presentation or during the first year after diagnosis. Despite marked growth retardation at birth, there was a significant improvement of growth after initiating insulin therapy. Four of the 5 patients had normal developmental milestones, one had mild developmental delay following a severe and prolonged attack of hypoglycemia. None of the patients had exocrine pancreatic deficiency. In summary, the very high rate of parental consanguinity, occurrence in both sexes and in two siblings in the same family, absence of islet cell antibodies and the presence of HLA-DR2 loci in 3/5 of patients suggest that PNIDDM is a different disease process to standard IDDM in childhood and an autosomal recessive mode of transmission.

Congenital lobar emphysema: a review of 10 cases.

We reviewed the clinical features and management of 10 patients with congenital lobar emphysema (CLE) treated in our institution over a period of seven years, from September 1988 to September 1995. The age of onset of symptoms ranged from few days from birth to six months. Correct diagnosis was made in only 4 patients before referral, even though diagnosis could have been arrived at from the chest radiograph in all of them. Lobectomy was done in seven patients, while one patient had vascular ring resected. Of the three patients managed conservatively, in one lobectomy was performed at the end of 5 months conservative course as her clinical condition deteriorated during an intercurrent chest infection. Of the remaining two, one has mild episodic reactive air way disease and the other patient is asymptomatic.

Growth hormone deficiency and empty sella in DIDMOAD syndrome: an endocrine study.

Two girls with DIDMOAD syndrome are presented. One also had severe megaloblastic-sideroblastic anaemia and the other several neurological manifestations. Both were short with defective growth hormone secretion. Computed tomography revealed empty sella in both girls; one had widespread atrophic cortical and cerebellar changes. High doses of thiamine improved the anaemia in the first case, increased C peptide secretion in both, but had no effect on the neurological abnormalities.