Two studies were carried out to examine the persistence (Study 1) and characteristics (Study 2) of mathematics learning disability (MLD) in girls with Turner syndrome or fragile X during the primary school years (ages 5-9 years). In Study 1, the rate of MLD for each syndrome group exceeded the rate observed in a grade-matched comparison group, although the likelihood of MLD persisting through the primary school years was comparable for all three groups. In Study 2, formal and informal math skills were compared across the syndrome groups, a normative group, and children from the normative group who had MLD. Few differences were observed between the Turner syndrome and normative groups. Despite having rote counting and number representation skills comparable to those in the normative group, girls with fragile X had difficulty with counting rules (e.g., cardinality, number constancy). However, this difficulty did not distingush them from the MLD group. Overall, counting skills appear to distinguish the Turner syndrome and fragile X groups, suggesting that the specificity of math deficits emerges earlier for fragile X than Turner syndrome.
Bibliographical noteFunding Information:
This work was supported by NIH grant HD R01 03461, and by a grant from the Spencer Foundation, both awarded to Michéle Mazzocco. The data presented and the views expressed are solely those of the authors. The authors thank the children who participated in the study, their parents and teachers, the staff at participating Baltimore County Public School elementary schools, and research assistant Stacy Chung. The authors acknowledge the outstanding contribution made by Gwen F. Myers, Project Coordinator for throughout the primary school years of this research.
- Fragile X syndrome
- Mathematics learning disability
- Turner syndrome