XP PSEUDOAUTOSOMAL GENE HAPLOINSUFFICIENCY AND LINEAR GROWTH DEFICIENCY IN 3 GIRLS WITH CHROMOSOME XP22-YQ11 TRANSLOCATION

Colony stimulating factor-2 receptor alpha (CSF2RA) and interleukin-3 receptor alpha (IL3RA), two genes from the chromosome Xp and Yp pseudo autosomal region (PAR), have been suggested as candidate genes for sho rt stature in Tur-ner syndrome, We report three girls with X;Y translo cation (46,X,der(X)t(X;Y) (p22;q11)) initially detected by amniocentes is, The terminal portion of the X chromosome distal to the translocati on breakpoint at Xp22 was deleted on the derivative X chromosome in al l three patients. Each had normal stature at birth, with greater than expected deceleration of growth velocity by the second year. Using flu orescence in situ hybridisation (FISH), we have shown deletion of the CSF2RA and IL3RA loci on the derivative X chromosomes of all three pat ients. The role of CSF2RA and IL3RA haploinsufficiency in linear growt h and final adult stature is discussed, Additional studies, particular ly of molecular deletions within the PAR, are needed to improve our un derstanding of the role of these and other PAR loci in the genetic con trol of adult stature.