The phenotype of ring chromosome 3.

A male child with mental retardation and poor growth was found to have a 46,XY,r3 (p26 leads to q29) karyotype in 92% of his peripheral lymphocytes and 90% of his cultured fibroblasts. Comparison of this patient's dysmorphic features with previously reported cases of ring 3 or deletion 3p suggests a clinical syndrome derived mainly from deletion of 3p26 leads to pter. The syndrome consists of mental retardation, pre- and postnatal growth retardation, microcephaly, hypertonia, digital anomalies, and a characteristic facies with ptosis, epicanthal folds, broad nasal root, down-turned corners of the mouth, and dysplastic ears.