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Consanguinity and Recessive Inheritance. Sarah Maund - Cardiff SCOBEC Training Day - Case Reports 15 th Oct ‘08. MUTYH-associated polyposis (MAP). Recessive form of colorectal cancer. Patients develop colorectal carcinomas and these are no different from those seen in sporadic cases.
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Consanguinity andRecessive Inheritance Sarah Maund - Cardiff SCOBEC Training Day - Case Reports 15th Oct ‘08
MUTYH-associated polyposis (MAP) • Recessive form of colorectal cancer. • Patients develop colorectal carcinomas and these are no different from those seen in sporadic cases. • Mostly present with carcinomas and the polyps are detected after colonoscopy. • More than 10 but less than thousands of polyps • Presents in the 5th or 6th decade. • Similar in presentation to FAP • Difficult to differentiate clinically from APC or certainly AFAP • Accounts for 20 to 30% of patients with polyposis coli in whom no mutations in the APC gene have been detected.
MAP Mutations • MAP is caused by bi-allelic mutations in the MUTYH gene. • It spans 7.1kb and is made up of 16 exons. • Mutations identified throughout the MUTYH gene, • mostly point, splice and small deletions/insertions. • The two most common mutations identified to date are • c.527A>G (p.Tyr176Cys) & c.1178G>A (p.Gly393Asp) • considered mainly north western European. • There are also two other mutations • c.303C>G (p.Tyr101X) & c.1427G>T (p.Glu477X) • predominantly found in the ‘Asian’ population.
Status Unknown Homozygous mutation Obligate Carrier Confirmed Carrier Mutation Negative ? ? ? ? ? ? Died of old age @ 106 Healthy throughout life Died in sleep age 88 ? ? ? ? ? ? ?
Status Unknown Homozygous mutation Obligate Carrier Confirmed Carrier Mutation Negative ? ? ? ? ? ? ? ? ? ? ? ? ? Patient has 200+ polyps (colonic). No family history. MUTYH analysis requested.
Status Unknown Homozygous mutation Obligate Carrier Confirmed Carrier Mutation Negative ? ? ? ? ? ? ? ? ? ? Y101X / Y101X
Status Unknown Homozygous mutation Obligate Carrier Confirmed Carrier Mutation Negative ? ? ? ? ? ? ? ? ? Y101X / Y101X
Status Unknown Homozygous mutation Obligate Carrier Confirmed Carrier Mutation Negative ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
Status Unknown Homozygous mutation Obligate Carrier Confirmed Carrier Mutation Negative ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
Status Unknown Homozygous mutation Obligate Carrier Confirmed Carrier Mutation Negative ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? N / Y101X
Status Unknown Homozygous mutation Obligate Carrier Confirmed Carrier Mutation Negative ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
Status Unknown Homozygous mutation Obligate Carrier Confirmed Carrier Mutation Negative ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
Status Unknown Homozygous mutation Obligate Carrier Confirmed Carrier Mutation Negative ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
Status Unknown Homozygous mutation Obligate Carrier Confirmed Carrier Mutation Negative ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
Status Unknown Homozygous mutation Obligate Carrier Confirmed Carrier Mutation Negative ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
Status Unknown Homozygous mutation Obligate Carrier Confirmed Carrier Mutation Negative ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
Status Unknown Homozygous mutation Obligate Carrier Confirmed Carrier Mutation Negative ? ? ? ? ? ? ? ? ? ? ? ? ? ?
Status Unknown Homozygous mutation Obligate Carrier Confirmed Carrier Mutation Negative ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
Status Unknown Homozygous mutation Obligate Carrier Confirmed Carrier Mutation Negative ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?