Growth hormone and distal trisomy 17qter

Sirs, The gene loci for growth hormone and chorionic somatomammotropin have been assigned to 17q21-qter by using rodent x human somatic cell hybrids and cloned probes (Owerbach et al. 1980, George et al. 1981). Imbalance of chromosome 17 is very rarely observed in liveborns. W e reported previously in this Journal a patient with mental retardation, congenital malformations, severe growth retardation, and trisomy 17q231qter (Turleau et al. 1979). Growth hormone was assayed in this patient by a radio immunology method after sequential stimulation by arginine and insulin, according to Penny et al. (1969). Results were within the normal range with a basal level of 2 ng/ml and peaks at 40 ng/ ml. This normal value could be explained: (1) by the absence of a gene dosage effect for growth hormone if the gene locus is located in 17q231qter; o r ( 2 ) by assigning the locus to 17q21q231, a segment within the region defined by gene localization but not within the region for which our patient is trisomic. References