Hepatitis A and B in non-institutionalized mentally retarded patients.

The high incidence of hepatitis A and B in institutionalized patients with Down's syndrome is not fully understood. Under poor hygienic conditions immunological alterations might predispose to these infections. To minimize environmental influences, 125 patients with Down's syndrome (mean age 11.9 years) living at home with their families were studied for the occurrence of serological markers of Hepatitis A and B. 106 outpatients with mental retardation of other genesis (mean age 12.4 years), and 114 consecutive voluntary blood donors (mean age 18.0 years) from the same area served as controls. Evidence of previous hepatitis A virus infection was found in 5.6% of Down's patients, in 9.4% of other mentally retarded patients, and in 16.7% of healthy controls. Evidence of previous or ongoing hepatitis B virus infection was a common finding in both groups of mental retardation (Down's syndrome 20.0%, other mentally retarded patients 11.3%) in sharp contrast to healthy blood donors (0.9%, p less than 0.05). Patients with Down's syndrome, however, revealed a much higher incidence of HBs-antigenemia as compared with other mentally retarded patients (12.8% vs. 2.8%, p less than 0.01). All HBs antigen-positive cases had normal transaminase levels and no overt clinical signs of liver disease, suggesting an asymptomatic carrier state. These data indicate that hepatitis A is not a special risk for mentally retarded outpatients, while hepatitis B virus infection is hyperendemic even in not-institutionalized patients.(ABSTRACT TRUNCATED AT 250 WORDS)