Molecular genetics of growth hormone deficient children: correlation with auxology and response to first year of growth hormone therapy.

Abstract

With the paucity of available literature correlating genetic mutation and response to treatment, we aimed to study the genetic makeup of children with growth hormone (GH) deficiency in Western India and correlate the mutation with auxology and response to GH treatment at end of 1 year. Fifty-three (31 boys and 22 girls) children with severe short stature (height for age z-score <-3) and failed GH stimulation test were studied. Those having concomitant thyroid hormone or cortisol deficiencies were appropriately replaced prior to starting GH treatment. A magnetic resonance imaging (MRI) brain scan was done in all. Genetic mutations were tested for in GH1, GHRH, LHX3, LHX4 and PROP1, POU1F1 and HESX1 genes. Mean age at presentation was 9.7±5.1 years. Thirty-seven children (Group A) had no genetic mutation detected. Six children (Group B) had mutations in the GH releasing hormone receptor (GHRHR) gene, while eight children (Group C) had mutation in the GH1 gene. In two children, one each had a mutation in PROP1 and LHX3. There was no statistically significant difference in baseline height, weight and BMI for age z-score and height velocity for age z-score (HVZ). HVZ was significantly lower, post 1 year GH treatment in the group with homozygous GH1 deletion than in children with no genetic defect. Response to GH at the end of 1 year was poor in children with the homozygous GH1 deletion as compared to those with GHRHR mutation or without a known mutation.