Influence of parental origin of the X chromosome on physical phenotypes and GH responsiveness of patients with Turner syndrome.

OBJECTIVE

Previous studies have reported the effects of parental origin of the X chromosome on specific phenotypic and cognitive profiles in Turner syndrome (TS). Here, we investigate the possible parent-of-origin effects on physical phenotypes and responsiveness to GH in Korean patients with TS.

DESIGN AND PATIENTS: Thirty-three patients with TS with nonmosaic karyotype and their parents participated in this study. The parental origin of the normal X chromosome was determined by comparing parental DNA polymorphisms using nine highly polymorphic microsatellite markers on the X chromosome. For the evaluation of parent-of-origin effects, typical phenotypic traits, including congenital malformations, auxological and endocrinological profiles, were compared.

RESULTS

The retained X chromosome was of maternal (X(m)) origin in 60.6% patients and paternal (X(p)) origin in 39.4% patients. No significant parent-of-origin effects on stature, body mass index, cardiac, renal, skeletal, lymphatic, hearing or ocular systems were evident. We observed no differences in height gain after GH treatment. In patients with the 45,X karyotype, patient height was positively correlated with maternal height in the X(m) group (r = 0.60, P = 0.04). Moreover, patient height was more significantly correlated with maternal than paternal height, irrespective of the parental origin of the retained X chromosome.

CONCLUSION

While we observed no significant impact of parental origin of the X chromosome on several phenotypic traits in patients with TS, a maternal imprinting effect on stature was suggested at least in patients with 45,X. Further studies on a larger number of patients with TS are essential to define the potential imprinting effects of undetermined genes on the X chromosome.