Cognitive functioning in Lesch-Nyhan syndrome: a 4-year follow-up study

Lesch-Nyhan syndrome (LNS) is a rare disorder of metabolism caused by a def ective gene on the X chromosome. It is typically characterized by choreoath etosis, hypertonia, hyperreflexia, and self-mutilation. The present study i s a 4-year follow-up investigation of the cognitive status of six subjects with a mean age of lr sears 10 months (range 14 years 9 months to 23 years) . The Stanford-Binet Intelligence Scale: IV was used. Each of the four doma ins assessed by this batters (verbal reasoning, abstract/visual reasoning, quantitative, and short-term memory) was compared with previous findings of the same subjects at their initial test and a-year follow up; the aim bein g to gain further insight into the clinical course of LNS over time. The re sults suggest that while the subjects generally continued to acquire new in formation and skills over time, their standardized scores declined, indicat ing that a plateau was reached in their skill levels relative to their peer s, as also seen in other developmental disabilities. Deficits were noted in working memory, particularly on tasks that involve considering multiple fe atures simultaneously.