TBCE and hypoparathyroidism-retardation-dysmorphism syndrome: KCS1 overlaps with the autosomal recessive Sanjad-Sakati syndrome (also known as hypoparathyroidism-growth retardation-dysmorphism syndrome [HRD], OMIM 241410), a disorder that has been reported principally in people of Arab descent living in the Middle East and in which medullary stenosis is far less common than KCS1 (10, 12–14).