Genetic components of perinatal morbidity and mortality.

The authors summarize the perinatal effects of the main genetic disorder groupings. Diseases of autosomal dominant inheritance are usually less severe and postnatal life is possible. Diseases of autosomal recessive inheritance are serious in most cases, causing severe symptoms in postnatal life. Diseases of X-linked recessive inheritance manifest themselves in male embryos and may be mild or serious; the more severe forms may influence the perinatal outcome. Diseases of X-linked dominant inheritance occur less frequently and manifest themselves in both sexes: in some cases the life expectancy is not favorable. Chromosomal anomalies, unbalanced rearrangements and autosomal trisomies may cause severe multiplex malformation syndromes and mental retardation. The diseases are serious in most cases and intrauterine mortality is high. Conversely, in cases of numerical differences of the sex chromosomes perinatal mortality does not increase remarkably, except in X-monosomy. Diseases of multifactorial origin lead to isolated malformations, but many civilization diseases originate from similar causes. In a few cases, severe diseases (i.e. congenital heart defects and neural tube defects) occur which may influence the outcome of the pregnancy. In terms of teratogenic effects, taking medication or undergoing X-ray examination or infections during early pregnancy indicates only a small risk in most cases. The authors emphasize that genetic centers significantly influence the perinatal outcome of pregnancies with their complex activity and their role in prenatal diagnostics.