Central Precocious Puberty in a Boy with Pseudohypoparathyroidism Type 1A due to a Novel GNAS Variant, Who Had Congenital Hypothyroidism as the First Manifestation.

Abstract

Pseudohypoparathyroidism type 1A (PHP1A) is a disorder of multiple hormone resistance, mainly parathyroid hormone. It is associated with Albright hereditary osteodystrophy phenotypes. Patients with PHP1A may initially present with hypothyroidism during infancy and later develop typical PHP1A characteristics during their childhood. Central precocious puberty (CPP) is extremely rare among PHP1A patients in whom gonadotropin resistance is more usual. This study reported a 9.5-year-old boy with congenital hypothyroidism who developed hypocalcemia secondary to pseudohypoparathyroidism. He had relatively short stature with height standard deviation score of -0.9. Obesity had been noted since the age of 2 years. At the presentation of pseudohypoparathyroidism, pubertal-sized testes of 10 mL were observed, and CPP was documented with serum testosterone concentration of 298 ng/dL (normal for Tanner stage III, 100-320), luteinizing hormone of 3.9 IU/L (normal, 0.2-5.0), and follicle-stimulating hormone of 4.8 IU/L (normal, 1.2-5.8). Pituitary magnetic resonance imaging was unremarkable. Genetic analysis confirmed the diagnosis of PHP1A with a novel heterozygous missense variant of GNAS gene in the exon 13, c.1103A>G (p.Asp368Gly). Awareness of PHP1A diagnosis in patients with congenital hypothyroidism and early childhood-onset obesity is crucial for early diagnosis. Apart from multiple hormone resistance, CPP could be manifested in patients with PHP1A.