A Rare Case of Adenosine Deaminase tRNA-Specific 3 Mutation, Adrenal Insufficiency, and Rhabdomyolysis.

Adenosine deaminase t-RNA-specific 3 (ADAT3) gene, present on chromosome 19, encodes for an enzyme responsible for deamination of adenosine to inosine. Individuals with ADAT3 mutation display microcephaly, dysmorphic features, neurological, behavioural, and endocrinal pathologies. ADAT3 mutation is a recognized cause of intellectual disability (ID) in Saudi Arabia, particularly amongst consanguineous families. Adrenal insufficiency (AI) is a life-threatening condition with variable clinical signs and symptoms, such as fatigue, nausea, vomiting, hypotension, hypoglycemia, and electrolyte imbalances. One very uncommon presentation of acute AI is rhabdomyolysis, a syndrome characterized by markedly elevated creatinine kinase (CK) levels, myoglobinuria, and muscle pain. We describe a case of an eight-year-old boy with ADAT3 mutation and growth hormone (GH) deficiency presenting with AI and rhabdomyolysis.

Hereditary 1,25-dihydroxyvitamin D-resistant rickets (HVDRR): clinical heterogeneity and long-term efficacious management of eight patients from four unrelated Arab families with a loss of function VDR mutation.

BACKGROUND: Vitamin D regulates the concentrations of calcium and phosphate in blood and promotes the growth and remodeling of bones. The circulating active form of vitamin D, 1,25-dihydroxyvitamin D, binds to the vitamin D receptor (VDR), which heterodimerizes with the retinoid X receptor to regulate the expression of target genes. Inactivating mutations in the VDR gene cause hereditary vitamin D-resistant rickets (HVDRR), a rare disorder characterized by an early onset of rickets, growth retardation, skeletal deformities, hypocalcemia, hypophosphatemia and secondary hyperparathyroidism, and in some cases alopecia. METHODS: We describe eight new HVDRR patients from four unrelated consanguineous families. The VDR gene was sequenced to identify mutations. The management of patients over a period of up to 11 years following the initial diagnosis is assessed. RESULTS: Although all patients exhibit main features of HVDRR and carry the same c.885C>A (p.Y295*) loss of function mutation in the VDR gene, there was heterogeneity of the manifestations of HVDRR-associated phenotypes and developmental milestones. These eight patients were successfully treated over a period of 11 years. All clinical symptoms were improved except alopecia. CONCLUSIONS: The study concludes that VDR sequencing and laboratory tests are essential to confirm HVDRR and to assess the effectiveness of the treatment.