Identification of two novel mutations in the human growth hormone receptor gene.

Deletions and mutations in the growth hormone receptor gene are the underlying etiology of Laron syndrome (LS). Most of the patients are distributed in and originating from the Mediterranean and Middle-Eastern countries. Thirty-nine mutations have been described so far. We hereby report 2 novel nonsense mutations, one in exon 2 found in three Jewish-Iraqi patients from Israel; and another in exon 6 found in an Italian girl. DNA sequencing of exon 2 revealed a G to A transition at nucleotide 83 in the fourth codon of the signal peptide (W-15X). In exon 6, a T to A transversion was found in amino acid 141 (L141X). Both mutations introduced a premature termination codon that led to a truncated non-functioning receptor. In addition we found in the Jewish-Iraqi patients, a mutation in exon 7 (R211H, previously described) and in the Italian family the polymorphism Gly168, in exon 6.