Association of Hypoparathyroidism-Retardation-Dysmorphism Syndrome (HRD) with Down syndrome

Hypoparathyroidism-Retardation-Dysmorphism (HRD) syndrome, also known as Sanjad Sakati Syndrome (SSS), is a rare autosomal recessive genetic condition seen in offspring of consanguineous parents of Middle Eastern origin. HRD consists of hypoparathyroidism leading to hypocalcemia and hyperphosphatemia, growth retardation, and characteristic dysmorphic features. This case presents a Saudi baby girl who was born to a first-degree consanguineous parent who previously had an affected baby with HRD. The patient’s facial features were suspicious of both HRD and Down syndrome. She was found to have complete atrioventricular septal defect on Echocardiogram which is the most common cardiac defect in Down syndrome. In addition, she developed hypocalcemia and hyperphosphatemia secondary to hypoparathyroidism. Surprisingly, Chromosomal analysis revealed Trisomy 21. The overall scenario of this case suggests a unique association of HypoparathyroidismRetardation-Dysmorphism syndrome (HRD) with Down syndrome.