FaCD Online Syndrome Fact Sheet

Last updated: 21 Feb 2008

Name: Constitutional deletion of 18p

Synonym: del(18p)

Mode of Inheritance: not applicable

Tumor features (possible)

gastric cancer

Non-tumor features

del(18)(p11) (constitutional)
developmental delay/mental deficiency/mental retardation
ears, malformed
growth deficieny
heart, congenital defect
large ears


18p- is a common constitutional chromosomal abnormality[1]. Dellavecchia et al.[2] reported the occurrence of gastric cancer in a 14-year-old girl with a de novo constitutional deletion of the short arm of chromosome 18. She also had a H.Pylori infection. Loss of the abnormal chromosome 18 was observed in the tumor. The authors postulated that the del(18p) may have favored loss of this abnormal chromosome in some gastric cells as an early step in gastric cancer oncogenesis, with the H.Pylori infection acting as a co-factor. Loss of 18q and to a lesser degree 18p has been observed in gastric cancer in general[3].


[1] Wester U, Bondeson ML, Edeby C, Annerén G. Clinical and molecular characterization of individuals with 18p deletion: a genotype-phenotype correlation. American journal of medical genetics. Part A 2006; 140(11):1164-71.
[2] Dellavecchia C, Guala A, Olivieri C, Haintink O, Cadario F, Luinetti O, Fiocca R, Minelli A, Danesino C, Bona G. Early onset of gastric carcinoma and constitutional deletion of 18p. Cancer Genet Cytogenet 1999; 113(1):96-99.
[3] Yu JC, Sun KL, Liu B, Fu SB. Allelotyping for loss of heterozygosity on chromosome 18 in gastric cancer. World journal of gastroenterology : WJG 2004; 10(13):1964-6.