Supplementary Material for: GH-Releasing Hormone Receptor Gene: A Novel Splice-Disrupting Mutation and Study of Founder Effects
2012-10-09T00:00:00Z (GMT) by
<b><i>Background:</i></b> Mutations in GH-releasing hormone receptor gene <i>(GHRHR)</i> are emerging as the most common cause of autosomal recessive isolated GH deficiency (IGHD). <b><i>Objective:</i></b> To search for <i>GHRHR</i> mutations in patients with familial or sporadic IGHD and to investigate founder effects in recurring mutations. <b><i>Methods:</i></b> The coding region of <i>GHRHR</i> was entirely amplified and sequenced from DNA of 18 patients with IGHD (16 unrelated) with topic posterior pituitary lobe on MRI. Haplotypes containing promoter SNPs and microsatellites flanking <i>GHRHR</i> were analyzed in patients with c.57+1G>A (IVS1+1G>A) mutation of our previously published kindred and also a Brazilian patient and 2 previously reported Japanese sisters with c.1146G>A (p.E382E) mutation. <b><i>Results:</i></b> A novel homozygous intronic <i>GHRHR</i> c.752-1G>A (IVS7-1G>A) mutation, predicting loss of the constitutive splice acceptor site, was identified in two siblings with IGHD. A compound heterozygous c.[57+1G>A];[1146G>A] and a heterozygous c.527C>T (p.A176V) were found in two sporadic cases. Haplotype analysis provided evidence for a founder effect for the c.57+1G>A mutation and independent recurrence for the c.1146G>A mutation. <b><i>Conclusion:</i></b> We report a novel splice-disrupting mutation in <i>GHRHR</i> in 2 siblings and provide evidence that all c.57+1G>A (IVS1+1G>A) mutant chromosomes have the same haplotype ancestor, indicating the occurrence of a founder effect in Brazilian patients with IGHD.