Neurocognitive profile in Turner's syndrome is not affected by growth impairment

Turner's syndrome (TS) is a chromosomal disorder that results from the loss of the entire or a part of the X-chromosome and occurs in 1/2,500 female births. According to the majority of specific reports, intelligence in TS is generally found to be normal and the prevalence of mental retardation does not seem to be increased in TS except for those patients with a small ring X-chromosome. We evaluated 33 girls with TS with chronological age from 6-18 years. Intellectual assessment included the WISC III and the WAIS-R scales. Our results showed: 1) mean full scale intelligence quotient (FSIQ) was significantly lower than expected based on normative data (p < 0.0005); 2) no correlation was present between height and general intellectual ability; 3) mean performance intelligence quotient (PIQ) was significantly lower than both mean verbal intelligence quotient (VIQ) and FSIQ (p < 0.0025 and p < 0.01, respectively), and most patients had a VIQ-PIQ discrepancy; 4) the frequency of mental retardation in our study group was significantly higher than that observed in the general population (15.1% vs 2.3%, p < 0.025); 5) a significant association was found between karyotype and VIQ, and the best score was achieved in the subgroup of patients with structural abnormalities of the X-chromosome. In the light of these findings we conclude that the clinical picture in TS may encompass a slightly reduced FSIQ, VIQ and especially an inadequate PIQ, but this neurocognitive profile is not significantly affected by statural impairment. Since these neurocognitive defects can be responsible for misdiagnosed school difficulties, we suggest that girls with TS should receive specialized educational support and multidisciplinary care.