A case with isolated growth hormone deficiency caused by compound heterozygous mutations in GH-1: a novel missense mutation in the initiation codon and a 7.6kb deletion.

OBJECTIVE

To characterize the cause of a sporadic isolated growth hormone deficiency in a single patient.

METHODS

Genomic DNA was extracted from blood samples of the patient and his family. Exons and exon-intron junctions of the GH-1 gene were amplified by PCR and sequenced. To characterize possible GH-1 deletions we performed Southern blot analysis and PCR-restriction fragment length analyses.

RESULTS

An adenine to guanine mutation at the first nucleotide of the initiation codon (Met ATGVal [GTG]) of the GH-1 gene was identified in the patient and the mother. A 7.6kb GH-1 deletion was identified in the patient, the brother and the father.

CONCLUSION

The patient was a compound heterozygote for an allele bearing a Met(-26)Val missense mutation inherited from his mother and an allele containing deletion of the entire GH-1 gene inherited from his father. The present missense mutation has not been described previously. Attention should be paid to the heterozygous gene deletion that is difficult to detect by PCR-based genetic analysis. The patient responded to GH replacement therapy fairly well, without developing anti-hGH antibody.