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Mapping of hereditary mixed polyposis syndrome (HMPS) to chromosome 10q23 by genomewide high-density single nucleotide polymorphism (SNP) scan and identification of BMPR1A loss of function
  1. X Cao1,
  2. K W Eu1,
  3. M P Kumarasinghe2,
  4. H H Li3,
  5. C Loi1,
  6. P Y Cheah1
  1. 1Department of Colorectal Surgery, Singapore General Hospital, Singapore 169608, Singapore
  2. 2Department of Pathology, Singapore General Hospital, Singapore 169608, Singapore
  3. 3Division of Clinical Trials and Epidemiological Sciences, National Cancer Center, Singapore 169608, Singapore
  1. Correspondence to:
 Peh Yean Cheah
 Department of Colorectal Surgery, Singapore General Hospital, Singapore 169608, Singapore; gcscpy{at}


Background: Hereditary mixed polyposis syndrome (HMPS) is characterised by colonic polyps of mixed histological types that are autosomal dominantly inherited and eventually lead to colorectal cancer (CRC). Study of the molecular basis of HMPS will enhance our knowledge of the genetic basis of the mixed polyposis-carcinoma sequence in both hereditary and sporadic CRC.

Methods/Results: We performed a genomewide linkage search on 15 members of a three-generation HMPS family using the GeneChip Human Mapping 10K Array and identified a 7 cM putative linkage interval on chromosome 10q23. Subsequently, 32 members from two HMPS families were typed with nine microsatellite markers spanning the region and the linkage was confirmed with a maximum multi-point logarithm of the odds (LOD) score of 4.6 (p<0.001). The 10q23.1–10q23.31 haplotypes segregate with the disease in both families. We screened for mutations in four candidate genes within the linkage region and identified an 11 bp deletion in the bone morphogenesis protein receptor 1A (BMPR1A) gene in one family.

Conclusions: Our results indicate that BMPR1A mutation accounts for HMPS. The data suggest that inactivating BMPR1A can initiate colorectal tumourigenesis via the mixed polyposis-carcinoma sequence.

  • CRC, colorectal cancer
  • FAP, familial adenomatous polyposis
  • GDAS, Genechip DNA Analysis
  • HMPS, hereditary mixed polyposis syndrome
  • ISC, intestinal stem cell
  • JPS, juvenile polyposis syndrome
  • LOD, logarithm of the odds
  • PCR, polymerase chain reaction
  • SGH, Singapore General Hospital
  • colorectal cancer
  • haplotype
  • linkage
  • mixed polyposis
  • whole-genome SNP genotyping

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  • This work is funded in part by grants from the National Medical Research Council (NMRC/0638/2002) and the Biomedical Research Council (03/1/27/19/257) of Singapore

  • Competing interests: none declared