A cytogenetic investigation of selected children with birth defects

Cytogenetic investigation of 46 selected children with birth defects was carried out by culture of peripheral leukocytes to determine (1) whether a chromosomal anomaly could be demonstrated, (2) the correlation between karyotype and phenotype, and (3) dosage effect in cases of aneuploidy by electrophoresis of serum proteins. This study revealed 20 abnormal chromosome complements and one XY sex chromosome complement in a phenotypic female. There was some individual variation in phenotype among those affected by a given chromosomal anomaly, probably due to differences in genetic background and in maternal host environment. Abnormalities in development common to two or more different chromosomal anomalies were also noted, mental deficiency being common to all. However, there was a relatively consistent and distinct overall pattern of development (phenotype) with each chromosomal abnormality, which should allow a specific clinical diagnosis