Identifying families at high risk for the Lynch syndrome (ie, hereditary nonpolyposis colorectal cancer) is critical for both genetic counseling and cancer prevention. Current clinical guidelines are ...effective but limited by applicability and cost.
To develop and validate a genetic counseling and risk prediction tool that estimates the probability of carrying a deleterious mutation in mismatch repair genes MLH1, MSH2, or MSH6 and the probability of developing colorectal or endometrial cancer.
External validation of the MMRpro model was conducted on 279 individuals from 226 clinic-based families in the United States, Canada, and Australia (referred between 1993-2005) by comparing model predictions with results of highly sensitive germline mutation detection techniques. MMRpro models the autosomal dominant inheritance of mismatch repair mutations, with parameters based on meta-analyses of the penetrance and prevalence of mutations and of the predictive values of tumor characteristics. The model's prediction is tailored to each individual's detailed family history information on colorectal and endometrial cancer and to tumor characteristics including microsatellite instability.
Ability of MMRpro to correctly predict mutation carrier status, as measured by operating characteristics, calibration, and overall accuracy.
In the independent validation, MMRpro provided a concordance index of 0.83 (95% confidence interval, 0.78-0.88) and a ratio of observed to predicted cases of 0.94 (95% confidence interval, 0.84-1.05). This results in higher accuracy than existing alternatives and current clinical guidelines.
MMRpro is a broadly applicable, accurate prediction model that can contribute to current screening and genetic counseling practices in a high-risk population. It is more sensitive and more specific than existing clinical guidelines for identifying individuals who may benefit from MMR germline testing. It is applicable to individuals for whom tumor samples are not available and to individuals in whom germline testing finds no mutation.
Constitutional MLH1 epimutations manifest as promoter methylation and silencing of the affected allele in normal tissues, predisposing to Lynch syndrome-associated cancers. This study investigated ...their frequency and inheritance.
A total of 416 individuals with a colorectal cancer showing loss of MLH1 expression and without deleterious germline mutations in MLH1 were ascertained from the Colon Cancer Family Registry (C-CFR). Constitutive DNA samples were screened for MLH1 methylation in all 416 subjects and for promoter sequence changes in 357 individuals.
Constitutional MLH1 epimutations were identified in 16 subjects. Of these, seven (1.7%) had mono- or hemi-allelic methylation and eight had low-level methylation (2%). In one subject the epimutation was linked to the c.-27C>A promoter variant. Testing of 37 relatives from nine probands revealed paternal transmission of low-level methylation segregating with a c.+27G>A variant in one case. Five additional probands had a promoter variant without an MLH1 epimutation, with three showing diminished promoter activity in functional assays.
Although rare, sequence changes in the regulatory region of MLH1 and aberrant methylation may alone or together predispose to the development of cancer. Screening for these changes is warranted in individuals who have a negative germline sequence screen of MLH1 and loss of MLH1 expression in their tumor.Genet Med 2013:15(1):25-35.
Germline mutations in the DNA base excision repair gene MUTYH are known to increase a carrier's risk of colorectal cancer. However, the risks of other (extracolonic) cancers for MUTYH mutation ...carriers are not well defined. We identified 266 probands (91% Caucasians) with a MUTYH mutation (41 biallelic and 225 monoallelic) from the Colon Cancer Family Registry. Mutation status, sex, age and histories of cancer from their 1,903 first‐ and 3,255 second‐degree relatives were analyzed using modified segregation analysis conditioned on the ascertainment criteria. Compared with incidences for the general population, hazard ratios (HRs) (95% confidence intervals CIs) for biallelic MUTYH mutation carriers were: urinary bladder cancer 19 (3.7–97) and ovarian cancer 17 (2.4–115). The HRs (95% CI) for monoallelic MUTYH mutation carriers were: gastric cancer 9.3 (6.7–13); hepatobiliary cancer 4.5 (2.7–7.5); endometrial cancer 2.1 (1.1–3.9) and breast cancer 1.4 (1.0–2.0). There was no evidence for an increased risk of cancers at the other sites examined (brain, pancreas, kidney or prostate). Based on the USA population incidences, the estimated cumulative risks (95% CI) to age 70 years for biallelic mutation carriers were: bladder cancer 25% (5–77%) for males and 8% (2–33%) for females and ovarian cancer 14% (2–65%). The cumulative risks (95% CI) for monoallelic mutation carriers were: gastric cancer 5% (4–7%) for males and 2.3% (1.7–3.3%) for females; hepatobiliary cancer 3% (2–5%) for males and 1.4% (0.8–2.3%) for females; endometrial cancer 3% (2%–6%) and breast cancer 11% (8–16%). These unbiased estimates of both relative and absolute risks of extracolonic cancers for people, mostly Caucasians, with MUTYH mutations will be important for their clinical management.
What's new?
People who have a mutation in the MUTYH gene have an increased risk of colorectal cancer. But are they also at higher risk for other types of cancer? In this study, the authors found that people with one mutated copy of MUTYH (monoallelic) have an increased risk of gastric, liver, breast and endometrial cancers, while people with two mutated copies (biallelic) have an increased risk of bladder and ovarian cancers. This information will be useful for risk assessment in patients and families who carry MUTYH mutations.
Purpose Regular use of aspirin is associated with improved survival for patients with colorectal cancer (CRC). However, the timing of and the subtype of CRC that would benefit the most from using ...aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) in relation to survival is unclear. Patients and Methods In all, 2,419 patients age 18 to 74 years with incident invasive CRC who were diagnosed from 1997 to 2008 were identified from population-based cancer registries in the United States, Canada, and Australia. Detailed epidemiologic questionnaires were administered at study enrollment and at 5-year follow-up. Survival outcomes were completed through linkage to national death registries. BRAF- and KRAS-mutation status, microsatellite instability, and CpG island methylator phenotype were also evaluated. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% CIs for overall survival (OS) and CRC-specific survival. Results After a median of 10.8 years of follow-up since diagnosis, 381 deaths (100 as a result of CRC) were observed. Compared with nonusers, postdiagnostic aspirin-only users had more favorable OS (HR, 0.75; 95% CI, 0.59 to 0.95) and CRC-specific survival (HR, 0.44; 95% CI, 0.25 to 0.71), especially among those who initiated aspirin use (OS: HR, 0.64; 95% CI, 0.47 to 0.86; CRC-specific survival: HR, 0.40; 95% CI, 0.20 to 0.80). The association between any NSAID use after diagnosis and OS differed significantly by KRAS-mutation status ( P
= .01). Use of any NSAID after diagnosis was associated with improved OS only among participants with KRAS wild-type tumors (HR, 0.60; 95% CI, 0.46 to 0.80) but not among those with KRAS-mutant tumors (HR, 1.24; 95% CI, 0.78 to 1.96). Conclusion Among long-term CRC survivors, regular use of NSAIDs after CRC diagnosis was significantly associated with improved survival in individuals with KRAS wild-type tumors.
Lynch syndrome is a highly penetrant cancer predisposition syndrome caused by germline mutations in DNA mismatch repair (MMR) genes. We estimated the risks of primary cancers other than colorectal ...cancer following a diagnosis of colorectal cancer in mutation carriers.
We obtained data from the Colon Cancer Family Registry for 764 carriers of an MMR gene mutation (316 MLH1, 357 MSH2, 49 MSH6, and 42 PMS2), who had a previous diagnosis of colorectal cancer. The Kaplan-Meier method was used to estimate their cumulative risk of cancers 10 and 20 years after colorectal cancer. We estimated the age-, sex-, country- and calendar period-specific standardized incidence ratios (SIRs) of cancers following colorectal cancer, compared with the general population.
Following colorectal cancer, carriers of MMR gene mutations had the following 10-year risk of cancers in other organs: kidney, renal pelvis, ureter, and bladder (2%, 95% confidence interval CI = 1% to 3%); small intestine, stomach, and hepatobiliary tract (1%, 95% CI = 0.2% to 2%); prostate (3%, 95% CI = 1% to 5%); endometrium (12%, 95% CI = 8% to 17%); breast (2%, 95% CI = 1% to 4%); and ovary (1%, 95% CI = 0% to 2%). They were at elevated risk compared with the general population: cancers of the kidney, renal pelvis, and ureter (SIR = 12.54, 95% CI = 7.97 to 17.94), urinary bladder (SIR = 7.22, 95% CI = 4.08 to 10.99), small intestine (SIR = 72.68, 95% CI = 39.95 to 111.29), stomach (SIR = 5.65, 95% CI = 2.32 to 9.69), and hepatobiliary tract (SIR = 5.94, 95% CI = 1.81 to 10.94) for both sexes; cancer of the prostate (SIR = 2.05, 95% CI = 1.23 to 3.01), endometrium (SIR = 40.23, 95% CI = 27.91 to 56.06), breast (SIR = 1.76, 95% CI = 1.07 to 2.59), and ovary (SIR = 4.19, 95% CI = 1.28 to 7.97).
Carriers of MMR gene mutations who have already had a colorectal cancer are at increased risk of a greater range of cancers than the recognized spectrum of Lynch syndrome cancers, including breast and prostate cancers.
Ehlers-Danlos syndrome type IV (EDS-IV) results from abnormal procollagen III synthesis and leads to arterial, intestinal, and uterine rupture. The purpose of this study was to review the spectrum, ...management, and clinical outcome of EDS-IV patients.
We retrospectively reviewed the clinical data of 31 patients (15 male and 16 female) with a clinical diagnosis of EDS-IV treated over a 30-year period (1971 to 2001). Biochemical confirmation was obtained in 24 patients, and mutation of the COL3A1 gene was confirmed in 11 patients. The study excluded patients with other connective tissue dysplasias.
The mean age at the time of diagnosis was 28.5 ± 11 years (range, 10 to 53 years). Twenty-four patients developed 132 vascular complications; of these, 85 were present either before or at the time of the initial evaluation, and 47 complications occurred during a median follow-up of 6.3 years (range, 0.5 to 26 years). Survival free of vascular complications was 90% at age 20 years, 39% at 40 years, and 20% at age 60 years. Fifteen patients underwent 30 operative interventions for vascular complications, including arterial reconstruction (n = 15), simple repair or ligation (n = 4), coil embolization (n = 3), splenectomy (n = 2), and abdominal decompression, nephrectomy, graft thrombectomy, vein stripping and thoracoscopy (n = 1 each). Three hospital deaths occurred from exsanguinating hemorrhage: two after operative interventions and one because of a ruptured splenic artery. Procedure-related morbidity was 46%, including a 37% incidence of postoperative bleeding and a 20% need for re-exploration. The incidence of late graft-related complications was 40% of arterial reconstructions, including 4 anastomotic aneurysms, 1 fatal anastomotic disruption, and 1 graft thrombosis. Patient survival was 68% at age 50 years and 35% at age 80 years. Of the 12 deaths during the study period, 11 were associated with vascular or graft-related complications.
Operative mortality in patients with vascular complications of EDS-IV was not excessively high, but the incidence of postoperative bleeding complications and late graft-related problems was significant. Despite successful repair of vascular complications, survival was shortened because of secondary vascular or graft-related complications.
Background
Despite regular surveillance colonoscopy, the metachronous colorectal cancer risk for mismatch repair (MMR) gene mutation carriers after segmental resection for colon cancer is high and ...total or subtotal colectomy is the preferred option. However, if the index cancer is in the rectum, management decisions are complicated by considerations of impaired bowel function. We aimed to estimate the risk of metachronous colon cancer for MMR gene mutation carriers who underwent a proctectomy for index rectal cancer.
Methods
This retrospective cohort study comprised 79 carriers of germline mutation in a MMR gene (18
MLH1,
55
MSH2,
4
MSH6,
and 2
PMS2
) from the Colon Cancer Family Registry who had had a proctectomy for index rectal cancer. Cumulative risks of metachronous colon cancer were calculated using the Kaplan–Meier method.
Results
During median 9 years (range 1–32 years) of observation since the first diagnosis of rectal cancer, 21 carriers (27 %) were diagnosed with metachronous colon cancer (incidence 24.25, 95 % confidence interval CI 15.81–37.19 per 1,000 person-years). Cumulative risk of metachronous colon cancer was 19 % (95 % CI 9–31 %) at 10 years, 47 (95 % CI 31–68 %) at 20 years, and 69 % (95 % CI 45–89 %) at 30 years after surgical resection. The frequency of surveillance colonoscopy was 1 colonoscopy per 1.16 years (95 % CI 1.01–1.31 years). The AJCC stages of the metachronous cancers, where available, were 72 % stage I, 22 % stage II, and 6 % stage III.
Conclusions
Given the high metachronous colon cancer risk for MMR gene mutation carriers diagnosed with an index rectal cancer, proctocolectomy may need to be considered.
Fragile X syndrome due to a missense mutation Myrick, Leila K; Nakamoto-Kinoshita, Mika; Lindor, Noralane M ...
European journal of human genetics,
10/2014, Volume:
22, Issue:
10
Journal Article
Peer reviewed
Open access
Fragile X syndrome is a common inherited form of intellectual disability and autism spectrum disorder. Most patients exhibit a massive CGG-repeat expansion mutation in the FMR1 gene that silences the ...locus. In over two decades since the discovery of FMR1, only a single missense mutation (p.(Ile304Asn)) has been reported as causing fragile X syndrome. Here we describe a 16-year-old male presenting with fragile X syndrome but without the repeat expansion mutation. Rather, we find a missense mutation, c.797G>A, that replaces glycine 266 with glutamic acid (p.(Gly266Glu)). The Gly266Glu FMR protein abolished many functional properties of the protein. This patient highlights the diagnostic utility of FMR1 sequencing.
We studied 2332 individuals with monoallelic mutations in MUTYH among 9504 relatives of 264 colorectal cancer (CRC) cases with a MUTYH mutation. We estimated CRC risks through 70 years of age of 7.2% ...for male carriers of monoallelic mutations (95% confidence interval CI, 4.6%–11.3%) and 5.6% for female carriers of monoallelic mutations (95% CI, 3.6%–8.8%), irrespective of family history. For monoallelic MUTYH mutation carriers with a first-degree relative with CRC diagnosed by 50 years of age who does not have the MUTYH mutation, risks of CRC were 12.5% for men (95% CI, 8.6%–17.7%) and 10% for women (95% CI, 6.7%–14.4%). Risks of CRC for carriers of monoallelic mutations in MUTYH with a first-degree relative with CRC are sufficiently high to warrant more intensive screening than for the general population.
Establishing the Amsterdam criteria, based on pedigrees, was essential for defining hereditary nonpolyposis colorectal cancer (HNPCC) syndrome in such a way that the underlying genetic cause could be ...identified. It is now known that about half of families that fulfill the original Amsterdam criteria have a hereditary DNA mismatch repair (MMR) gene mutation. These families may be said to have Lynch syndrome. The other half of families with HNPCC has no evidence of DNA MMR deficiency, and studies show that these families are different from families with Lynch syndrome. Familial colorectal cancer type X is the name used to refer to the "other half of HNPCC".
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