Triple-A syndrome (MIM 231550; also known as Allgrove syndrome) is an autosomal recessive disorder characterized by adrenocorticotropin hormone (ACTH)-resistant adrenal insufficiency, achalasia of the oesophageal cardia and alacrima. Whereas several lines of evidence indicate that triple-A syndrome results from the abnormal development of the autonomic nervous system, late-onset progressive neurological symptoms (including cerebellar ataxia, peripheral neuropathy and mild dementia) suggest that the central nervous system may be involved in the disease as well. Using fine-mapping based on linkage disequilibrium in North African inbred families, we identified a short ancestral haplotype on chromosome 12q13 (<1 cM), sequenced a BAC contig encompassing the triple-A minimal region and identified a novel gene (AAAS) encoding a protein of 547 amino acids that is mutant in affected individuals. We found five homozygous truncating mutations in unrelated patients and ascribed the founder effect in North African families to a single splice-donor site mutation that occurred more than 2,400 years ago. The predicted product of AAAS, ALADIN (for alacrima-achalasia-adrenal insufficiency neurologic disorder), belongs to the WD-repeat family of regulatory proteins, indicating a new disease mechanism involved in triple-A syndrome. The expression of the gene in both neuroendocrine and cerebral structures points to a role in the normal development of the peripheral and central nervous systems.
Two major points are emphasized in this series: 1) the presence in 7 histologically analyzed streak gonads of a homogeneous 45,X chromosomal complement suggests that the invasion of the primitive genital ridge by a such a cell line may induce abnormal gonadal development; 2) 3 males, apparently normal at birth, developed late onset abnormalities such as dysgenetic testes leading to infertility, Ulrich-Turner stigmata, dysmorphic features, and mild mental retardation. These data indicate the importance of an accurate clinical and histologic evaluation of any patient presenting with 45, X/46,XY mosaicism.
To improve criteria for entry into future trials of immunosuppression, we enrolled 40 children with recent-onset Type I insulin-dependent diabetes in a pilot trial of cyclosporine. Twenty-seven patients were able to discontinue insulin therapy 48 +/- 5 days after the start of immunosuppression. At four months, their fasting and postprandial blood glucose concentrations averaged 110 and 160 mg per deciliter (6.1 and 8.9 mmol per liter) with a mean hemoglobin A1c level of 6.15 percent. Seventy-five percent of these patients with early remission still did not need insulin at 12 months, and their glycemic control was similar to that at 4 months. The major differences between the 27 patients with remission and the 13 without remission were the duration of symptoms before diagnosis (26.8 vs. 48.0 days, P less than 0.01), the degree of weight loss (3.2 vs. 10 percent of body weight, P less than 0.001), the initial hemoglobin A1c level (10.7 vs. 13.2 percent, P less than 0.001), and the frequency of ketoacidosis (11 vs. 61.5 percent, P less than 0.001). The lesser degree of weight loss was the strongest independent predictor of remission. The response of C-peptide to intravenous glucagon (0.50 vs. 0.17 pmol per milliliter, P less than 0.05) was also an independent predictor. No differences were observed between the two groups of patients in age, sex, HLA phenotype, autoantibodies to insulin or islet-cell antigens, or doses or trough levels of cyclosporine. Only minimal manifestations of toxicity were detected over the period of observation. We conclude that early treatment with cyclosporine in children with recent-onset Type I diabetes can induce remission from insulin dependence, with half the patients not requiring insulin after a full year.
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