Assessment of clinical findings can improve the rate of detection of mutations of DNA mismatch-repair genes in families suspected of having hereditary nonpolyposis colorectal cancer.

Heterozygous fumarate hydratase (FH) germline mutations cause hereditary leiomyomatosis and renal cell cancer (HLRCC), an autosomal dominant syndrome characterized by multiple cutaneous piloleiomyomas, uterine leiomyomas and papillary type 2 renal cancer. The main objective of our study was to evaluate clinical and genetic data from families suspected of HLRCC on a nationwide level. All families referred for FH mutation analysis in the Netherlands were assessed. We performed FH sequence analysis and multiplex ligation-dependent probe amplification. Families with similar FH mutations were examined for haplotype sharing. In 14 out of 33 families, we identified 11 different pathogenic FH germline mutations, including 4 novel mutations and 1 whole-gene deletion. Clinical data were available for 35 FH mutation carriers. Cutaneous leiomyomas were present in all FH mutation carriers older than 40 years of age. Eleven out of 21 female FH mutation carriers underwent surgical treatment for symptomatic uterine leiomyomas at an average of 35 years. Two FH mutation carriers had papillary type 2 renal cancer and Wilms' tumour, respectively. We evaluated the relevance of our findings for clinical practice and have proposed clinical diagnostic criteria, indications for FH mutation analysis and recommendations for management.

AimsWith more than 40 dilated cardiomyopathy (DCM)-related genes known, genetic analysis of patients with idiopathic DCM is costly and time-consuming. We describe the yield from genetic analysis in DCM patients in a large Dutch cohort. Methods and resultsWe collected cardiological and neurological evaluations, family screenings, and genetic analyses for 418 index patients with idiopathic DCM. We identified 35 (putative) pathogenic mutations in 82 index patients (20%). The type of DCM influenced the yield, with mutations found in 25% of familial DCM cases, compared with 8% of sporadic DCM cases and 62% of cases where DCM was accompanied by neuromuscular disease. A PLN founder mutation (43 cases) and LMNA mutations (19 cases, 16 different mutations) were most prevalent and often demonstrated a specific phenotype. Other mutations were found in: MYH7, DES, TNNT2, DMD, TPM1, DMPK, SCN5A, SGCB (homozygous), and TNNI3. After a median follow-up of 40 months, the combined outcome of death from any cause, heart transplantation, or malignant ventricular arrhythmias in patients with a mutation was worse than in those without an identified mutation (hazard ratio 2.0, 95% confidence interval 1.4 -3.0). This seems to be mainly attributable to a high prevalence of malignant ventricular arrhythmias and end-stage heart failure in LMNA and PLN mutation carriers. ConclusionThe yield of identified mutations in DCM index patients with clinical clues, such as associated neuromuscular disease or familial occurrence, is higher compared with those without these clues. For sporadic DCM, specific clinical characteristics may be used to select cases for DNA analysis.--

Since the discovery of the first causative mutations for cardiomyopathies in the early 1990s, the importance of inherited genetic variants has been increasingly recognized. 1,2 These discoveries have led to a better understanding of disease pathogenesis and introduced genetic evaluation into clinical practice for affected individuals and their relatives. 2,3 Editorial see p 405 Clinical Perspective on p 465Early identification of asymptomatic mutation carriers via genetic cascade screening is potentially of major prognostic importance because cardiomyopathies can lead to sudden cardiac death (SCD) as a result of malignant ventricular arrhythmias even before the onset of any symptoms.2 Although our knowledge of the genetics of cardiomyopathies has expanded greatly, mutation carriers are mostly advised, among other as to lifestyle adjustments (ie, sports activity), and treated based on general guidelines based on their cardiac morphological and functional characteristics; there is little known about specific genotype-phenotype relationships. 2,4 Phospholamban (encoded by the PLN gene) is a transmembrane sarcoplasmic reticulum phosphoprotein and is a key Background-The pathogenic phospholamban R14del mutation causes dilated and arrhythmogenic right ventricular cardiomyopathies and is associated with an increased risk of malignant ventricular arrhythmias and end-stage heart failure. We performed a multicentre study to evaluate mortality, cardiac disease outcome, and risk factors for malignant ventricular arrhythmias in a cohort of phospholamban R14del mutation carriers. Methods and Results-Using the family tree mortality ratio method in a cohort of 403 phospholamban R14del mutation carriers, we found a standardized mortality ratio of 1.7 (95% confidence interval, 1.4-2.0) with significant excess mortality starting from the age of 25 years. Cardiological data were available for 295 carriers. In a median follow-up period of 42 months, 55 (19%) individuals had a first episode of malignant ventricular arrhythmias and 33 (11%) had an end-stage heart failure event. The youngest age at which a malignant ventricular arrhythmia occurred was 20 years, whereas for an end-stage heart failure event this was 31 years. Independent risk factors for malignant ventricular arrhythmias were left ventricular ejection fraction <45% and sustained or nonsustained ventricular tachycardia with hazard ratios of 4.0 (95% confidence interval, 1.9-8.1) and 2.6 (95% confidence interval, 1.5-4.5), respectively. Conclusions-Phospholamban R14del mutation carriers are at high risk for malignant ventricular arrhythmias and endstage heart failure, with left ventricular ejection fraction <45% and sustained or nonsustained ventricular tachycardia as independent risk factors. High mortality and a poor prognosis are present from late adolescence. regulator of calcium homeostasis. 5 Pathogenic mutations in PLN, mostly leading to inhibition of the calcium uptake into the sarcoplasmic reticulum, may cause inherited cardiomyopathy. 5 The pathogenic PLN R14del ...

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BackgroundRecently, we showed that the c.40_42delAGA (p.Arg14del) mutation in the phospholamban (PLN) gene can be identified in 10–15 % of Dutch patients with dilated cardiomyopathy or arrhythmogenic cardiomyopathy. The arrhythmogenic burden of the p.Arg14del mutation was illustrated by the high rate of appropriate ICD discharges and a positive family history for sudden cardiac death.MethodsOur goal was to evaluate the geographical distribution and the origin of this specific mutation in the Netherlands and to get an estimation of the prevalence in a Dutch population cohort. Therefore, we investigated the postal codes of the places of residence of PLN p.Arg14del mutation carriers and places of birth of their ancestors. In addition, a large population-based cohort (PREVEND) was screened for the presence of this mutation.ResultsBy April 2012, we had identified 101 probands carrying the PLN p.Arg14del mutation. A total of 358 family members were also found to carry this mutation, resulting in a total of 459 mutation carriers. The majority of mutation carriers live in the northern part of the Netherlands and analysing their grandparents’ places of birth indicated that the mutation likely originated in the eastern part of the province of Friesland. In the PREVEND cohort we identified six heterozygous PLN p.Arg14del mutation carriers out of 8,267 subjects (0.07 %).ConclusionThe p.Arg14del mutation in the PLN gene is the most frequently identified mutation in Dutch cardiomyopathy patients. The mutation that arose 575–825 years ago is likely to have originated from the eastern part of the province of Friesland and is highly prevalent in the general population in the northern part of the Netherlands.

Age, family history, aortic size and syndromic features determine who is advised to have genetic testing as well as screening of first-degree relatives. There is a need for more prospective multicenter studies to optimize current recommendations.