The cognitive phenotype of Turner syndrome: Specific learning disabilities

Abstract

Global descriptors of the cognitive phenotype of Turner syndrome are well established and are thus commonly referred to. For example, Turner syndrome is a proposed etiology of the nonverbal learning disability - because of reported relative strengths in verbal skills, and relatively weaker nonverbal skills - particularly in arithmetic, select visuospatial skills, and processing speed. This profile is observed throughout and beyond the school age years. Reliance on this gross level description of the cognitive profile (e.g., nonverbal learning disability) may be helpful as a starting point when determining whether an individual with Turner syndrome has educational needs, but it carries limited practical significance when determining the specific nature of these needs. The limitations stem from the fact that the severity of the cognitive profile is highly variable among individuals with Turner syndrome; that the "nonverbal" difficulties are specific rather than widespread; and that any individual with Turner syndrome may also manifest cognitive characteristics independent of Turner syndrome. In view of the increased risk for specific cognitive difficulties, a detailed assessment prior to the onset of formal schooling (or at the time of diagnosis, when diagnosis occurs after 5 years of age) can play an important role in determining school readiness and potential need for educational support among individual girls with Turner syndrome.

Fig. 1

Full scale IQ scores of 20 individual girls with Turner syndrome and their own mothers. The paired set of data points appears in order of smallest to largest discrepancy between mothers (▲) and their own daughters (●). The girls ranged in age from 7 to 10 years at the time of their IQ assessment.

Fig. 2

Verbal (VIQ) and Performance IQ (PIQ) scores of 20 individual girls with Turner syndrome and their own mothers. The paired set of data points appears in order of smallest to largest discrepancy between mothers (▲) and their own daughters (●).

Fig. 3

Verbal and Performance IQ score discrepancies vary across individual girls with Turner syndrome.