Common deletion variants causing protocadherin-α deficiency contribute to the complex genetics of BAV and left-sided congenital heart disease.

Bicuspid aortic valve (BAV) with ~1%-2% prevalence is the most common congenital heart defect (CHD). It frequently results in valve disease and aorta dilation and is a major cause of adult cardiac surgery. BAV is genetically linked to rare left-heart obstructions (left ventricular outflow tract obstructions [LVOTOs]), including hypoplastic left heart syndrome (HLHS) and coarctation of the aorta (CoA). Mouse and human studies indicate LVOTO is genetically heterogeneous with a complex genetic etiology. Homozygous mutation in the Pcdha protocadherin gene cluster in mice can cause BAV, and also HLHS and other LVOTO phenotypes when accompanied by a second mutation. Here we show two common deletion copy number variants (delCNVs) within the PCDHA gene cluster are associated with LVOTO. Analysis of 1,218 white individuals with LVOTO versus 463 disease-free local control individuals yielded odds ratios (ORs) at 1.47 (95% confidence interval [CI], 1.13-1.92; p = 4.2 × 10-3) for LVOTO, 1.47 (95% CI, 1.10-1.97; p = 0.01) for BAV, 6.13 (95% CI, 2.75-13.7; p = 9.7 × 10-6) for CoA, and 1.49 (95% CI, 1.07-2.08; p = 0.019) for HLHS. Increased OR was observed for all LVOTO phenotypes in homozygous or compound heterozygous PCDHA delCNV genotype comparison versus wild type. Analysis of an independent white cohort (381 affected individuals, 1,352 control individuals) replicated the PCDHA delCNV association with LVOTO. Generalizability of these findings is suggested by similar observations in Black and Chinese individuals with LVOTO. Analysis of Pcdha mutant mice showed reduced PCDHA expression at regions of cell-cell contact in aortic smooth muscle and cushion mesenchyme, suggesting potential mechanisms for BAV pathogenesis and aortopathy. Together, these findings indicate common variants causing PCDHA deficiency play a significant role in the genetic etiology of common and rare LVOTO-CHD.

Fabry Disease in Families With Hypertrophic Cardiomyopathy: Clinical Manifestations in the Classic and Later-Onset Phenotypes.

BACKGROUND: The screening of Icelandic patients clinically diagnosed with hypertrophic cardiomyopathy resulted in identification of 8 individuals from 2 families with X-linked Fabry disease (FD) caused by GLA(α-galactosidase A gene) mutations encoding p.D322E (family A) or p.I232T (family B). METHODS AND RESULTS: Familial screening of at-risk relatives identified mutations in 16 family A members (8 men and 8 heterozygotes) and 25 family B members (10 men and 15 heterozygotes). Clinical assessments, α-galactosidase A (α-GalA) activities, glycosphingolipid substrate levels, and in vitro mutation expression were used to categorize p.D322E as a classic FD mutation and p.I232T as a later-onset FD mutation. In vitro expression revealed that p.D322E and p.I232T had α-GalA activities of 1.4% and 14.9% of the mean wild-type activity, respectively. Family A men had markedly decreased α-GalA activity and childhood-onset classic manifestations, except for angiokeratoma and cornea verticillata. Family B men had residual α-GalA activity and developed FD manifestations in adulthood. Despite these differences, all family A and family B men >30 years of age had left ventricular hypertrophy, which was mainly asymmetrical, and had similar late gadolinium enhancement patterns. Ischemic stroke and severe white matter lesions were more frequent among family A men, but neither family A nor family B men had overt renal disease. Family A and family B heterozygotes had less severe or no clinical manifestations. CONCLUSIONS: Men with classic or later-onset FD caused by GLA missense mutations developed prominent and similar cardiovascular disease at similar ages, despite markedly different α-GalA activities.

Thoracic aortic disease in two patients with juvenile polyposis syndrome and SMAD4 mutations.

Dilation or aneurysm of the ascending aorta can progress to acute aortic dissection (Thoracic Aortic Aneurysms and Aortic Dissections, TAAD). Mutations in genes encoding TGF-ß-related proteins (TGFBR1, TGFBR2, FBN1, and SMAD3) cause syndromic and inherited TAAD. SMAD4 mutations are associated with juvenile polyposis syndrome (JPS) and a combined JPS-hereditary hemorrhagic telangiectasia (HHT) known as JPS-HHT. A family with JPS-HHT was reported to have aortic root dilation and mitral valve abnormalities. We report on two patients with JPS-HHT with SMAD4 mutations associated with thoracic aortic disease. The first patient, an 11-year-old boy without Marfan syndrome features, had JPS and an apparently de novo SMAD4 mutation (c.1340_1367dup28). Echocardiography showed mild dilation of the aortic annulus and aortic root, and mild dilation of the sinotubular junction and ascending aorta. Computed tomography confirmed aortic dilation and showed small pulmonary arteriovenous malformations (PAVM). The second patient, a 34-year-old woman with colonic polyposis, HHT, and features of Marfan syndrome, had a SMAD4 mutation (c.1245_1248delCAGA). Echocardiography showed mild aortic root dilation. She also had PAVM and hepatic focal nodular hyperplasia. Her family history was significant for polyposis, HHT, thoracic aortic aneurysm, and dissection and skeletal features of Marfan syndrome in her father. These two cases confirm the association of thoracic aortic disease with JPS-HHT resulting from SMAD4 mutations. We propose that the thoracic aorta should be screened in patients with SMAD4 mutations to prevent untimely death from dissection. This report also confirms that SMAD4 mutations predispose to TAAD.