By means of a screening based on genotyping of patients with low plasma enzymatic activity, the prevalence of FD in our population of HCM is 1% (0.9% in men and 1.1% in women). This diagnosis is relevant, because it allows the identification of disease carriers that might benefit from enzyme replacement therapy.
LVNC and HCM may appear as overlapping entities. The ACTC E101K mutation should be considered in the genetic diagnosis of LVNC, apical HCM, and septal defects.
ObjectivesThe prognostic value of genetic studies in cardiomyopathies is still controversial. Our objective was to evaluate the outcome of patients with cardiomyopathy with mutations in the converter domain of β myosin heavy chain (MYH7).MethodsClinical characteristics and survival of 117 affected members with mutations in the converter domain of MYH7 were compared with 409 patients described in the literature with mutations in the same region.ResultsTwenty-five mutations were evaluated (9 in our families including 3 novel (Ile730Asn, Asp717Gly and Arg719Pro)). Clinical diagnoses were hypertrophic (n=407), dilated (n=15), non-compaction (n=4) and restrictive (n=5) cardiomyopathies, unspecified cardiomyopathy (n=11), sudden death (n=50) and 35 healthy carriers. One hundred eighty-four had events (cardiovascular death or transplant). Median event-free survival was 50±2 years in our patients and 53±3 years in the literature (p=0.27). There were significant differences in the outcome between mutation: Ile736Thr had fewer events than other mutations in the region (p=0.01), while Arg719Gln (p<0.01) had reduced event-free survival.ConclusionsMutations in the converter region are generally associated with adverse prognosis although there are differences between mutations. The identification of a mutation in this particular region provides important prognostic information that should be considered in the clinical management of affected patients.
BackgroundMyBPC3 mutations are amongst the most frequent causes of hypertrophic cardiomyopathy, however, its prevalence varies between populations. They have been associated with mild and late onset disease expression. Our objectives were to establish the prevalence of MyBPC3 mutations and determine their associated clinical characteristics in our patients.MethodsScreening by Single Strand Conformation Polymorphisms (SSCP) and sequencing of the fragments with abnormal motility of the MyBPC3 gene in 130 unrelated consecutive HCM index cases. Genotype-Phenotype correlation studies were done in positive families.Results16 mutations were found in 20 index cases (15%): 5 novel [D75N, V471E, Q327fs, IVS6+5G>A (homozygous), and IVS11-9G>A] and 11 previously described [A216T, R495W, R502Q (2 families), E542Q (3 families), T957S, R1022P (2 families), E1179K, K504del, K600fs, P955fs and IVS29+5G>A]. Maximum wall thickness and age at time of diagnosis were similar to patients with MYH7 mutations [25(7) vs. 27(8), p = 0.16], [46(16) vs. 44(19), p = 0.9].ConclusionsMutations in MyBPC3 are present in 15% of our hypertrophic cardiomyopathy families. Severe hypertrophy and early expression are compatible with the presence of MyBPC3 mutations. The genetic diagnosis not only allows avoiding clinical follow up of non carriers but it opens new possibilities that includes: to take preventive clinical decisions in mutation carriers than have not developed the disease yet, the establishment of genotype-phenotype relationship, and to establish a genetic diagnosis routine in patients with familial HCM.
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