Background. Many observations indicate that genetic factors play an important role in the aetiology of autism.
Up to now, however, no genetic markers have been convincingly identified which influence the predisposition to
this disorder. Complex genetic analysis of autistic patients and their families may therefore lead to the identification
of features which could help to direct further search for the predisposing genes.
Methods and Results. We have analysed a sample of 20 patients with autism spectrum disorders. The patients
have been subjected to clinical genetic examination, cytogenetic analysis and DNA analysis of the FMR1 gene. In
the sample studied we have observed more boys (15/20), various degree ofmental retardation (18/20), high frequency
of complications during pregnancy (10/20) and delivery (10/20), increased incidence of psychiatric disorders,
behavioural abnormities and suicides among the relatives, and increased head circumference and unusually formed
ears in the probands. Three patients had different chromosomal aberrations or variants (t(21;22), inv(9) and inv(10)).
One patient harboured expansion of the trinucleotide repeat sequence in the FMR1 gene on the full mutation level
which is characteristic for the fragile X syndrome, and one patient is suspected to suffer from the Rett syndrome.
Conclusions. Our observations confirm and extend the results reported in the literature.Most interesting aremainly
the macrocephaly which may be associated with the recently described increased neonatal levels of neural growth
factors in autistic individuals, ear malformations which may indicate aberrations in the HOXA1 gene pathway, the
occurrence of chromosomal inversions recurrent in autism, and peculiarities in the pedigrees of the patients.
autism, pregnancy complications, genetic load, macrocephaly, ear shape abnormalities, chromosomal
inversions, FMR1 gene, fragile X syndrome, Rett syndrome.