Cytogenetic investigations in 817 dysmorphic babies

: By means of G-, C-, and Q-banding techniques 817 dysmorphic children under 1 year of age were cytogenetically investigated. 184 cases of Down's syndrome, 54 cases of various numerical or structural autosomal aberrations, and 29 cases of gonosomal aberration were discovered. The criteria of dysmorphia are the following: intra-, and/or extrauterine retardation, occurrence of minor and/or major malformations, dysfunction of the central nervous system, and the ambiguity of the external genitals, respectively. The proper evaluation of the dysmorphic signs markedly increases the efficiency of the cytogenetical studies. According to the results, the principles applied in 16 patients the background of the dysmorphic features of a pericentric inversion of chromosome No 9 could be disclosed. This phenomenon earlier regarded as polymorphism or normal variant seems to be playing an important role in the etiology of unspecified dysmorphic syndromes. The early detection of a chromosomal aberration ensures the correct judgment of the diagnosis and the prognosis of the patient and by tracking down the carrier family members helps in the prevention, too.