Types 1 diabetes mellitus and Graves' disease in Sanjad-Sakati syndrome: a case report in Saudi Arabia.

Sanjad-Sakati syndrome (SSS) is a rare autosomal recessive disorder caused by TBCE gene variants and characterized by congenital hypoparathyroidism, severe growth retardation, developmental delay, and dysmorphic features. We report a nine-year-old Saudi boy with genetically confirmed SSS due to a homozygous 12-bp deletion in exon 3 of the TBCE gene (c.155_166del12bp; p.S52_G55del), who presented with hypocalcemic convulsions at three weeks of age. At three years, he developed type 1 diabetes mellitus (T1DM) with profound insulin deficiency and positive anti-islet cell and anti-GAD-65 antibodies. At four years, he developed Graves' disease, confirmed by hyperthyroidism, positive TSH receptor antibodies, and increased thyroid vascularity, followed by hypothyroidism requiring levothyroxine. Severe bilateral medullary nephrocalcinosis was also identified. This case highlights the unusual coexistence of TBCE-related SSS, autoimmune T1DM, and Graves' disease, raising the possibility of potential immune dysregulation, although causality cannot be established. Longitudinal endocrine surveillance, particularly of thyroid function, may be warranted in patients with SSS.