In this report, an atypical case of Noonan syndrome (NS) associated with sarcomeric hypertrophic cardiomyopathy (HCM) in a 33-year-old patient was described. Genetic testing revealed two different dis Show more
In this report, an atypical case of Noonan syndrome (NS) associated with sarcomeric hypertrophic cardiomyopathy (HCM) in a 33-year-old patient was described. Genetic testing revealed two different disease-causing mutations: a mutation in the PTPN11 gene, explaining NS, and a mutation in the MYBPC3 gene, known to be associated with HCM. This case exemplifies the challenge in achieving a definite etiological diagnosis in patients with HCM and the need to exclude other diseases mimicking this condition (genocopies or phenocopies). Compound heterozygous mutations are rare but possible in HCM patients. In conclusion, this study highlights the important role of genetic testing as a necessary diagnostic tool for performing a definitive etiological diagnosis of HCM. Show less
Hypertrophic cardiomyopathy is a relatively frequent disease with a prevalence of 0.2% worldwide and a remarkable genetic heterogeneity, with more than 30 causative genes reported to date. Current PCR Show more
Hypertrophic cardiomyopathy is a relatively frequent disease with a prevalence of 0.2% worldwide and a remarkable genetic heterogeneity, with more than 30 causative genes reported to date. Current PCR-based strategies are inadequate for genomic investigations involving many candidate genes. Here, we report a next-generation sequencing procedure associated with DNA sequence capture that is able to sequence 202 cardiomyopathy-related genes simultaneously. We developed a complementary data analysis pipeline to select and prioritize genetic variants. The overall procedure can screen a large number of target genes simultaneously, thereby potentially revealing new disease-causing and modifier genes. By using this procedure, we analyzed hypertrophic cardiomyopathy patients in a shorter time and at a lower cost than with current procedures. The specificity of the next-generation sequencing-based procedure is at least as good as other techniques routinely used for mutation searching, and the sensitivity is much better. Analysis of the results showed some novel variants potentially involved in the pathogenesis of hypertrophic cardiomyopathy: a missense mutation in MYH7 and a nonsense variant in INS-IGF2 (patient 1), a splicing variant in MYBPC3 and an indel/frameshift variant in KCNQ1 (patient 2), and two concomitant variations in CACNA1C (patient 3). Sequencing of DNA from the three patients within a pool allowed detection of most variants identified in each individual patient, indicating that this approach is a feasible and cost-effective procedure. Show less