Cao et al. (2006) described two 3-generation Singapore Chinese families with hereditary mixed polyposis (HMPS), noting that the 15 affected members had colonic polyps very similar to those of the HMPS1 family 'SM96' described by Thomas et al. ... Cao et al. (2006) described two 3-generation Singapore Chinese families with hereditary mixed polyposis (HMPS), noting that the 15 affected members had colonic polyps very similar to those of the HMPS1 family 'SM96' described by Thomas et al. (1996), with polyps showing hyperplastic, adenomatous, or juvenile-type morphology. Juvenile-type polyps were documented in only 4 individuals and were atypical, associated with hyperplastic changes. One-third of patients were documented to have polyps with mixed juvenile and hyperplastic or mixed hyperplastic and adenomatous components on different visits. The mean age of diagnosis in these families was 32.4 years. More than half of the patients had polyps throughout the large bowel; 3 individuals from each family eventually developed colorectal cancer.
In affected members of a 3-generation Singapore Chinese family (family 2) with hereditary mixed polyposis, Cao et al. (2006) identified heterozygosity for an 11-bp deletion in the BMPR1A gene (601299.0009). The deletion was not found in unaffected family ... In affected members of a 3-generation Singapore Chinese family (family 2) with hereditary mixed polyposis, Cao et al. (2006) identified heterozygosity for an 11-bp deletion in the BMPR1A gene (601299.0009). The deletion was not found in unaffected family members. In 2 affected members of 'family 1,' direct sequencing of all exons and flanking sequences of candidate genes BMPR1A, PTEN (601728), MINPP1 (605391), and PCDH21 (609502) revealed no detectable mutations.