Obesity, round face, brachydactyly and mental retardation in a boy with hypocalcemia

We report the case of a boy aged 10 years and 6 months, presenting with obesity, dysmorphic signs as round-shaped face, hypertelorism, sparse lateral eye-brows, low nasal bridge, short neck, absence of the central incisors, short III-IV metacarpal and III-IV-V metatarsal bones, mental retardation and biochemical abnormalities as hypocalcemia, hyperphosphathemia and elevated serum parathyroid hormone (PTH) levels. The physical features are all reported in Albright Hereditary Osteodystrophy (AHO), an autosomal dominant condition caused by mutations in the GNASI gene. The associated biochemical abnormalities suggested an end-organ failure to respond to the action of PTH, which allowed its to make the diagnosis of pseudohypoparathyroidism (PHP) type Ia. This condition is caused by a mutation in the maternal allele. On the contrary the mutation of the paternal allele leads to a PHP variant called pseudo-pseudohypoparathyroidism, characterized by AHO without hormone resistance. The clinical diagnosis of these conditions can be today confirmed by molecular analysis.