Facial dysmorphism, growth and developmental retardation, absence of early vocalization, and other anomalies in two siblings

We report two siblings, born to nonconsanguineous parents, who have a similar pattern of findings, including symmetric intrauterine growth retardation with postnatal growth failure, facial dysmorphism, deficient vocalization, microcephaly, and developmental delay. Late prophase karyotype analysis at the 800-band stage in the first child revealed 46,XY/46,XY der (11) mosaicism. Similar studies performed in both parents and in the second sibling revealed normal karyotypes. The etiology of this syndrome is unknown. Autosomal recessive inheritance is suggested by the occurrence in two siblings, but an unbalanced chromosomal duplication syndrome cannot be ruled out; chromosomal analysis of fibroblasts obtained by skin biopsy may prove helpful in distinguishing between these two possibilities.