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.
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.


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.
Cao
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Eu
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Kumarasinghe
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Loi
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Cheah
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D011125:Adenomatous Polyposis Coli / Q000235:genetics*; D052005:Bone Morphogenetic Protein Receptors, Type I / Q000235:genetics*; D002874:Chromosome Mapping; D002879:Chromosomes, Human, Pair 10; D015179:Colorectal Neoplasms / Q000235:genetics; D005260:Female; D015894:Genome, Human; D005838:Genotype; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats; D009154:Mutation; D010375:Pedigree; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide
C498211:BMPR1A protein, human; D052005:Bone Morphogenetic Protein Receptors, Type I