INFANTILE AUTISM: A GENETIC STUDY OF 21 TWIN PAIRS

TLDR

Uncertainty remains on both the mode of inheritance and exactly what is inherited. A systematic study of 21 same‑sex twin pairs (11 monozygotic and 10 dizygotic) in which at least one twin exhibited infantile autism was conducted. The study found a 36 % concordance for autism in monozygotic twins versus 0 % in dizygotic twins, 82 % versus 10 % concordance for cognitive abnormalities, evidence of hereditary influence on cognitive deficits, and that brain injury in infancy can cause autism alone or with genetic predisposition.

Abstract

Summary A systematic study was made of a representative group of 21 same‐sexed twin pairs (11 MZ and 10 DZ) in which at least one twin showed the syndrome of infantile autism. There was a 36 per cent pair‐wise concordance rate for autism in MZ pairs compared with o per cent concordance in DZ pairs. The concordance for cognitive abnormalities was 82 per cent in MZ pairs and 10 per cent in DZ pairs. It was concluded that there were important hereditary influences concerning a cognitive deficit which included but was not restricted to autism. In 12 out of 17 pairs discordant for autism, the presence of autism was associated with a biological hazard liable to cause brain damage. It was concluded that brain injury in the infancy period may lead to autism on its own or in combination with a genetic predisposition. Uncertainty remains on both the mode of inheritance and exactly what is inherited.