Neurocognitive functions and behavioral profiles in children with nephropathic cystinosis

Children with nephropathic cystinosis (NCTN) have evidence of defective intellectual functions and behavioral disorders. This prospective study was performed to detect the cognitive dysfunctions in patients with this rare hereditary lysosomal storage disease, define their behavioral phenotypes, and study the findings on magnetic resonance imaging (MRI) of the brain. Thirteen patients with confirmed diagnosis of cystinosis (mean age±SD 5.9±3.0, range 1.5-12 years) were subjected to the Stanford Binet test, Porteus Maze test, Child Behavior Checklist, and MRI brain. Thirteen age- and sex-matched children served as the control subjects (mean age±SD 5.9±2.9, range 1.7-12 years). The intelligence quotient (IQ) was significantly lower in patients with cystinosis (P<0.001), with a significant defect in verbal (language, memory, and comprehension) and non-verbal abilities (visual perception and visiospatial and motor performance). A discrepancy between both abilities was detected--the non-verbal ability being lower; however, it did not reach statistical significance. Furthermore, analysis revealed the visiospatial ability to be significantly lower compared to the visual perception. In comparison to healthy controls, children with NCTN had evidence of increased incidence of behavioral problems, mainly social (P=0.023). An MRI of the brain revealed varying degrees of atrophic changes in seven patients. Patients with NCTN need a wider scope of attention and care, encompassing not only the metabolic multisystem derangement, but also the neuropsychological impairment in the context of multidisciplinary management. This approach is crucial in formulating comprehensive plans for social and educational rehabilitation.