[Clinical and genetic features of left ventricular noncompaction: a continuum in cardiomyopathies]. / Clinica e genetica del ventricolo sinistro non compatto: conferma di un continuum nelle cardiomiopatie.

Isolated left ventricular non-compaction (LVNC) is a rare genetic form of cardiomyopathy (CM) characterized by prominent left ventricular wall trabeculation and intertrabecular recesses communicating with the ventricular cavity. Clinical signs are variable, ranging from lack of symptoms to severe manifestations including heart failure, sustained ventricular arrhythmias, cardioembolism and sudden death. The diagnosis of LVNC is frequently missed, due to limited awareness in the medical community. Contemporary diagnostic sensitivity has been enhanced by the introduction of specific morphologic criteria by high resolution echocardiography and cardiac magnetic resonance. As a consequence, LVNC has been diagnosed more frequently in association with other disorders such as congenital heart disease or genetic CM. The clinical relevance of regional non-compaction in the context of other cardiac diseases is still uncertain. Recent evidence points to an overlapping genetic background encompassing LVNC, hypertrophic and dilated CM, suggesting a continuum of disease associated with sarcomere protein gene mutations. This concept may prove relevant to the understanding of common pathogenetic mechanisms of CM and offer novel research opportunities.

A molecular screening strategy based on beta-myosin heavy chain, cardiac myosin binding protein C and troponin T genes in Italian patients with hypertrophic cardiomyopathy.

BACKGROUND: Mutations causing hypertrophic cardiomyopathy (HCM) have been described in nine different genes of the sarcomere. Three genes account for most known mutations: beta-myosin heavy chain (MYH7), cardiac myosin binding protein C (MYBPC3) and cardiac troponin T (TNNT2). Their prevalence in Italian HCM patients is unknown. Thus, we prospectively assessed a molecular screening strategy of these three genes in a consecutive population with HCM from two Italian centres. METHODS: Comprehensive screening of MYBPC3, MYH7 and TNNT2 was performed in 88 unrelated HCM patients by denaturing high-performance liquid chromatography and automatic sequencing. RESULTS: We identified 32 mutations in 50 patients (57%); 16 were novel. The prevalence rates for MYBPC3, MYH7 and TNNT2 were 32%, 17% and 2%, respectively. MYBPC3 mutations were 18, including two frameshift, five splice-site and two nonsense. All were 'private' except insC1065 and R502Q, present in three and two patients, respectively. Moreover, E258K was found in 14% of patients, suggesting a founder effect. MYH7 mutations were 12, all missense; seven were novel. In TNNT2, only two mutations were found. In addition, five patients had a complex genotype [i.e. carried a double MYBPC3 mutation (n = 2), or were double heterozygous for mutations in MYBPC3 and MYH7 (n = 3)]. CONCLUSIONS: The first comprehensive evaluation of MYBPC3, MYH7 and TNNT2 in an Italian HCM population allowed a genetic diagnosis in 57% of the patients. These data support a combined analysis of the three major sarcomeric genes as a rational and cost-effective initial approach to the molecular screening of HCM.