Functional study of DAND5 variant in patients with Congenital Heart Disease and laterality defects

Abstract

BackgroundPerturbations on the Left-Right axis establishment lead to laterality defects, with frequently associated Congenital Heart Diseases (CHDs). Indeed, in the last decade, it has been reported that the etiology of isolated cases of CHDs or cases of laterality defects with associated CHDs is linked with variants of genes involved in the Nodal signaling pathway.MethodsWith this in mind, we analyzed a cohort of 38 unrelated patients with Congenital Heart Defects that can arise from initial perturbations in the formation of the Left-Right axis and 40 unrelated ethnically matched healthy individuals as a control population. Genomic DNA was extracted from buccal epithelial cells, and variants screening was performed by PCR and direct sequencing. A Nodal-dependent luciferase assay was conducted in order to determine the functional effect of the variant found.ResultsIn this work, we report two patients with a DAND5 heterozygous non-synonymous variant (c.455G > A) in the functional domain of the DAND5 protein (p.R152H), a master regulator of Nodal signaling. Patient 1 presents left isomerism, ventricular septal defect with overriding aorta and pulmonary atresia, while patient 2 presents ventricular septal defect with overriding aorta, right ventricular hypertrophy and pulmonary atresia (a case of extreme tetralogy of Fallot phenotype). The functional analysis assay showed a significant decrease in the activity of this variant protein when compared to its wild-type counterpart.ConclusionAltogether, our results provide new insight into the molecular mechanism of the laterality defects and related CHDs, priming for the first time DAND5 as one of multiple candidate determinants for CHDs in humans.Electronic supplementary materialThe online version of this article (doi:10.1186/s12881-017-0444-1) contains supplementary material, which is available to authorized users.

The Role of Cerl2 in the Establishment of Left-Right Asymmetries during Axis Formation and Heart Development

“…Atrial septal defects have also been reported in our mouse mutants before [ 22 ]. Moreover, in agreement with the mouse results, a variant in the functional domain of DAND5 protein (human Cerl2) has recently been identified in our lab, in patients with both CHD and laterality defects [ 47 ].…”

“…Several mouse Cerl2 orthologues have been reported, and those that show close similarities at the protein level are human DAND5 ( p = 65%), CHARON in zebrafish ( p = 55%), Xenopus COCO ( p = 53%), and chick CERBERUS ( p = 51%). All these Cerl2 orthologues have a conserved essential role in LR axis development [ 47 , 50 , 51 , 52 ], moreover, x Coco and z Charon have been reported to share two important characteristics with m Cerl2 : they display a right-sided bias of expression that responds to ciliary leftward-driven flow [ 53 , 54 ]. However, so far none of these orthologues have been reported to have an independent role in cardiogenesis.…”

Congenital heart disease risk loci identified by genome-wide association study in European patients

“…Each of these genetic abnormalities are associated with roughly 10% of CHDs, while the majority of cases seem to represent a complex multifactorial disease with unknown etiology (9). An increasing number of candidate genes have been implicated, which are likely to cause CHD (10)(11)(12) and genetic variations are suggesting obvious heterogeneity (13)(14)(15). Furthermore, these studies strongly support the idea that certain variants are inherited and may cause a pronounced pathology.…”

Biallelic DAW1 variants cause a motile ciliopathy characterized by laterality defects and subtle ciliary beating abnormalities

“…These specialized cilia rotate to induce a leftward flow of embryonic fluid detected by immotile cilia around the node periphery, 5 inducing left-sided activation of the NODAL cascade. 6,7 Many pathomolecular processes underlie nonsyndromic laterality defects, including impaired NODAL signaling (eg, DAND5 8,9 ) and motile (eg, DNAH9 10 ) and sensory cilia dysfunction (eg, PKD2 11 ). However, along with otosinopulmonary PCD symptoms, laterality defects are invariably due to defective assembly, motility, or organization of motile cilia.…”