Cerebrospinal fluid monoamines in Down's syndrome adults at different ages.

Markers of monoamine metabolism in lumbar cerebrospinal fluid (CSF) and plasma were determined in nine young, healthy adults with trisomy 21 Down's syndrome (DS), 21-34-years-old, and in three DS subjects over 45 years, two of whom were demented, as well as in two groups of age-matched controls. Test scores of general intelligence, visuospatial ability, visual discrimination and verbal intelligence were reduced significantly in the old as compared to the young DS subjects. Dementia in DS was evident from a history of mental deterioration, disorientation and hallucinations. In the young DS adults, as compared to the controls, CSF 5-HIAA and norepinephrine were significantly elevated but plasma levels were unchanged. HVA, MHPG and biopterin did not differ between the DS groups and age-matched controls, or with relation to age in the DS or control subjects. These results suggest an increased turnover of monoamines in young adults with DS but that alterations in monoamine metabolism are unrelated to the cognitive decline with age in DS.