Molecular genetics of Turner syndrome: correlation with clinical phenotypeand response to growth hormone therapy

To correlate the origin of the retained X in Turner syndrome with phenotype , pre-treatment height and response to recombinant human growth hormone (rh GH) therapy, systematic clinical assessment and molecular studies were carr ied out in 33 Greek children with Turner syndrome and their parents includi ng Is children with 45,X and 15 with X-mosaicism. Microsatellite markers on X chromosomes (DXS101 and DXS337) revealed that the intact X was paternal (Xp) in 15/30 and maternal (Xm) in 15/30 children, while 3/33 families were non-informative. No significant relationship was found between parental or igin of the retained X and birth weight/length/gestational age, blepharopto sis, pterygium colli, webbed neck, low hairline, abnormal ears, lymphoedema , short 4th metacarpal, shield chest, widely spaced nipples, cubitus valgus , pigmented naevi, streak gonads, and cardiovascular/renal anomalies. With regard to the children's pre-treatment height, there was a significant corr elation with maternal height and target height in both Xm and Xp groups. No differences were found between Xm and Xp groups and the improvement of gro wth velocity (GV) during the first and second year of rhGH administration, while for both groups GV significantly improved with rhGH by the end of the first and the second year. To our knowledge. this is the first attempt to correlate the parental origin of Turner syndrome with the response to rhGH therapy.