Correlates of language impairment in children with galactosaemia.

PURPOSE

This study describes risk factors associated with language impairment in children with classic galactosaemia.

METHOD

Thirty-three 4-16-year-old participants with classic galactosaemia and a history of speech sound disorders completed a battery of cognitive and language measures and their parents completed a family history questionnaire.

RESULTS

Nine of the sixteen (56%) participants with typical cognitive development and 15 of the 17 (88%) with borderline-low cognitive development had language impairments. Participants with typical cognitive development more often had an expressive language disorder, whereas those with borderline-low cognitive development more often had a mixed receptive-expressive language disorder. Participants with Q188R/Q188R genotypes had increased risk for both cognitive and language impairments. The IQs of younger siblings who did not consume milk postnatally were 10-56 points higher than the IQs of their older siblings with galactosaemia who had consumed milk postnatally. However, 4 of 5 younger siblings who were lactose-restricted from birth had language impairments. Typically-reported risk factors for language disorder, including parental history of speech/learning problems and low parental education level, were not significantly associated with cognitive or language impairments in the present sample of children with galactosaemia.

CONCLUSIONS

Children with galactosaemia and speech disorders have a 4-6 times greater risk for language impairment than children with early speech disorders of unknown origin. Early dietary lactose may increase the risk for cognitive and language impairments; however, the lack of significant associations of language impairment with days of milk consumption, and other familial and educational risk factors, is consistent with prenatal causation.