MOLECULAR-GENETIC ANALYSIS OF THE GROWTH- HORMONE LOCUS IN A CHILEAN FAMILY

The first and so far the only form of isolated growth hormone deficien cy to accede to molecular genetic analysis is IGHD 1A, which has an au tosomal recessive mode of inheritance. Several sizes of growth hormone gene deletions, ranging from 6.7 to 8.5 Kb are responsible for IGHD 1 A. It has been reported that children with IGHD IA have an initial goo d response to growth hormone treatment, followed by growth failure ass ociated with the development of blocking antibodies against growth hor mone. The effectiveness of treatment has been associated to the size o f the gene deletion. We performed a molecular genetic analysis of the growth hormone locus, using Southern Blot and PCR techniques, to a 12 years old girl who fulfilled the criteria for IGHD 1A and her closer r elatives. The results showed a 7 Kb deletion for the growth hormone ge ne in the girl and one of her borthers.