Cognitive, behavioural and adaptive profiles of children with glutaric aciduria type I detected through newborn screening

Abstract

Glutaric aciduria type I (GA I) is an autosomal recessive disorder of lysine and tryptophan metabolism due to a deficiency in glutaryl-CoA dehydrogenase activity. Recent reports suggest that early diagnosis through newborn screening and initiation of preventive therapy result in improved functional outcome; however, detailed neuropsychological profiles of children with GA I are seldom reported and thus the impact of the disease on cognition, motor abilities and behaviour remains uncertain. We present detailed neuropsychological profiles of three children who were diagnosed with GA I through newborn screening and treated from early age, and one asymptomatic patient diagnosed through cascade screening. A comprehensive battery of standardized tests was administered including measures of intellectual function, attention/memory, executive function, motor skills, speech/language, as well as behavioural and adaptive skills. The results reveal overall average cognitive outcomes; however, subtle, but significant, fine motor and articulation deficits were observed. The results are discussed with regard to potential links between fine motor deficits and speech impairments in children with GA I. Such difficulties can impact on the child's ability to engage in academic, leisure and daily activities. These findings highlight the importance of in-depth assessments of all aspects of neuropsychological function in patients with GA I and provide a basis for future neuropsychological assessment in similar groups of children. In spite of relatively preserved overall functioning, using a broad range of sensitive cognitive and motor measures facilitates the detection of subtle deficits, and allows for planning of early and adequate therapeutic interventions.