A Case of Inherited GH Deficiency with a 6.7-kb Deletion of GH-1 Gene

Abstract

We report a case of inherited isolated GH deficiency (IGHD) type IA. The patient (S.A.) is a 15-year-old boy with a chief complaint of short stature. His parents were second cousins. He was delivered of normal size without asphyxia or fetal distress. His growth retardation became prominent 3 months after birth. When he was admitted to Tohoku University Hospital at the age of 3 years and 1 month, his height was 68.3 cm (-7.1 SD), his body wt was 7.5 kg, and his bone age was 10 months. His plasma GH level measured with a high sensitivity GH immunoradiometric assay (IRMA) kit was below the detection level (6 pg/ml) either after sequential 3 day administrations of GH releasing hormone (GHRH) followed by arginine infusion, or after GH releasing peptide (GHRP) administration. His other endocrine functions remained normal. No abnormalities were observed in his hypothalamo-pituitary region by magnetic resonance imaging. Among 5 patients with IGHD whose GH levels were undetectable even after the stimulation with GHRH plus arginine, 2 patients (including the above case) still did not show any response to GHRP. Genetic analyses of the GH-1 gene were undergone in these 5 patients, and revealed that only the patient S.A. had a homozygous 6.7-kb GH-1 gene deletion. His parents, sisters, and paternal grandfather were heterozygotes. The patient was therefore diagnosed as IGHD type IA. We consider that the measurement of plasma GH with the high sensitivity GH IRMA kit after strong GH provocation tests may be useful for the screening of IGHD type IA.