Adolescent growth in homozygous sickle-cell disease is delayed but follows a normal pattern - abstract

Sickle-cell disease is known to lead to increased incidence of the major neurological complication, stroke. The findings of several studies suggest that it can also give rise to less obvious neurological sequelae that manifest in more subtle clinical signs and deficits in neuropsychological functioning, particularly intellectual functioning. It is known, however, that chronic illnesses such as sickle-cell disease are associated with psychosocial factors such as school absenteeism and decreased activity that could also contribute to intellectual impairment. This study examined intellectual status and activity scale scores in 60 adolescents with homozygous (SS) sickle-cell disease and no history of stroke, compared to 60 normal (AA) controls matched for age, sex and socioeconomic background. All subjects were taken from a cohort group followed from birth at the sickle-cell clinic, MRC Laboratories Kingston, Jamaica. School attendance was examined in those subjects still attending school. Sickle-cell disease was found to be related to significant lowering of intelligence test scores (IQ) by 5.6 points on average, suggesting intellectual impairment. There was no relationship between school absenteeism, activity level and genotype or IQ, suggesting psychosoical factors did not contribute to lowered IQ in this group. Patterns of IQ scores in subjects with the disease suggested the likelihood of organicity, of a diffuse or generalized nature. Results suggest that IQ levels in sickle-cell disease are generally lower than in normal children and that this is likely to be the result of subtle neurological complications, even in the absence of stroke. Pathogenesis and onset are not at present known but merit further investigation (AU)