Cri-du-chat syndrome: A correlation between abnormalities and size of deletion

Twelve patients (8 females; 4 males) with cri-du-chat syndrome (5p-) were studied to correlate abnormalities with the amount of chromosomal deletion. All were retarded but the younger patients and those with consistent early educational intervention scored higher on IQ testing. Institutionalized individuals and those with significant perinatal difficulties had low scores. Those whose deletion is in the 5th (terminal) band have a significantly higher IQ and are able to use language to communicate effectively. Some function well enough to learn minimal academic skills and/or work at sheltered employment facilities. Most of the physical abnormalities were present in 75% or more and none except height and weight seemed related to the deletion size. The number of distinct dermatoglyphic abnormalities found was increased in those whose deletions were in the 4th and 3rd bands. Normal hexosaminidase B levels in all substantiated that the genetic locus for that enzyme is below the 3rd band. Early determination of the amount of chromosome deletion may help predict future potential.