A Unique Case of a Child with Two Rare Hereditary Diseases: Familial Dilated Cardiomyopathy and Arterial Calcification.

Here, we present a unique case of the combination of two rare hereditary diseases-a familial form of dilated cardiomyopathy (DCM) and arterial calcification (AC)-in a 10-month-old boy. DCM was caused by a novel pathogenic nucleotide variant (NV) c.542G>T in the MYH7 gene, and AC was caused by biallelic nucleotide variants c.3421C>T and c.4015C>T in the ABCC6 gene. NVs were identified by the next-generation sequencing (NGS) of a broad panel of 404 genes potentially involved in cardiovascular disorders and subsequently validated by Sanger sequencing in the proband and his parents. Cardiologic examinations confirmed the familial nature of cardiomyopathy and the pathogenicity of variant c.542G>T in MYH7 gene. This case highlights the clinical utility of NGS in identifying complex co-existing hereditary conditions and emphasizes the need for the comprehensive genetic testing of patients with atypical clinical presentations.