<unk>  is<unk> e to a partial deletion of the short arm of chromosome number 5, also called "5p monosomy" or "partial monosomy." Approximately 90% of cases result from a sporadic, or randomly occurring, de novo deletion. The remaining 10–15% are<unk> e to unequal segregation of a parental balanced translocation where the 5p monosomy is often accompanied by a trisomic portion of the genome. These individuals may have more severe disease than those with isolated monosomy of 5p. A recent study suggests this may not be the case where a trisomy of chromosome 4q is involved. Most cases involve total loss of the most distal 10–20% of the material on the short arm. Fewer than 10% of cases have other rare cytogenetic aberrations (e.g., interstitial deletions, mosaicisms, rings and de novo translocations). The deleted chromosome 5 is paternal in origin in about 80% of de novo cases. Loss of a small region in band 5p15.2 <unk> <unk> <unk> <unk> tical region) correlates with all the clinical features of the syndrome with the exception of the catlike cry, which maps to band 5p15.3 (catlike<unk> tical region). The results suggest that 2 noncontiguous<unk> tical regions contain genes involved in this condition's cause. Two genes in these regions, Semaphorine F (SEMA5A) and delta catenin (CTNND2), are potentially involved in cerebral development. The deletion of the telomerase reverse transcriptase (hTERT) gene localized in 5p15.33 may contribute to the phenotypic changes in<unk>  as well.
Cri du chat syndrome
Lazarus syndrome
Lucey–Driscoll syndrome
Pork–cat syndrome
Woodhouse–Sakati syndrome
ANOTHER syndrome
Roemheld syndrome
Johanson–Blizzard syndrome