Familial factors and hearing impairment modulate the neuromotor phenotype in Turner syndrome

In Turner syndrome (TS), an X-chromosomal anomaly characterised by total or partial loss of the second X-chromosome, muscle hypotonia, and lower proficiency in fine and gross motor skills have been described. It is assumed that the neuromotor phenotype in TS is linked with X-chromosomal factors (individual mosaicism) and with the oestrogen deficiency due to streak gonads. From studies in normal populations, a further risk factor may be recurrent otitis media (OM), which occurs frequently in TS, often in combination with hearing impairment (HI). It is also likely that familial factors are involved. The aim of our study was to specify the respective impact of the interindividual varying status of mosaicism and of hypergonadotropic hypogonadism as well as of the risk factors recurrent OM and HI in comparison to familial coinfluences on the neuromotor proficiency (MOP) in TS. We used the Bruininks-Oseretsky Test of Motor Proficiency to examine 105 subjects with TS (mean age 9.4 years; SD 3.3 years) and 52 sisters (mean age 9.8 years; SD 3.7 years). Significant correlations were found for familial covariance regarding the relation between TS subjects and their sisters (r=0.42, P<0.01) and HI and MOP (r=-0.39, P<0.01) Conclusion: we conclude that the familial influences and risk factors such as recurrent otitis media in combination with hearing impairment serve primarily as important predictors of the individual neuromotor phenotype in Turner syndrome.