Functional analysis of germline VANGL2 variants using rescue assays of vangl2 knockout zebrafish.

Developmental studies have shown that the evolutionarily conserved Wnt Planar Cell Polarity (PCP) pathway is essential for the development of a diverse range of tissues and organs including the brain, spinal cord, heart and sensory organs, as well as establishment of the left-right body axis. Germline mutations in the highly conserved PCP gene VANGL2 in humans have only been associated with central nervous system malformations, and functional testing to understand variant impact has not been performed. Here we report three new families with missense variants in VANGL2 associated with heterotaxy and congenital heart disease p.(Arg169His), non-syndromic hearing loss p.(Glu465Ala) and congenital heart disease with brain defects p.(Arg135Trp). To test the in vivo impact of these and previously described variants, we have established clinically-relevant assays using mRNA rescue of the vangl2 mutant zebrafish. We show that all variants disrupt Vangl2 function, although to different extents and depending on the developmental process. We also begin to identify that different VANGL2 missense variants may be haploinsufficient and discuss evidence in support of pathogenicity. Together, this study demonstrates that zebrafish present a suitable pipeline to investigate variants of unknown significance and suggests new avenues for investigation of the different developmental contexts of VANGL2 function that are clinically meaningful.

Next-generation sequencing in a series of 80 fetuses with complex cardiac malformations and/or heterotaxy.

Herein, we report the screening of a large panel of genes in a series of 80 fetuses with congenital heart defects (CHDs) and/or heterotaxy and no cytogenetic anomalies. There were 49 males (61%/39%), with a family history in 28 cases (35%) and no parental consanguinity in 77 cases (96%). All fetuses had complex CHD except one who had heterotaxy and midline anomalies while 52 cases (65%) had heterotaxy in addition to CHD. Altogether, 29 cases (36%) had extracardiac and extra-heterotaxy anomalies. A pathogenic variant was found in 10/80 (12.5%) cases with a higher percentage in the heterotaxy group (8/52 cases, 15%) compared with the non-heterotaxy group (2/28 cases, 7%), and in 3 cases with extracardiac and extra-heterotaxy anomalies (3/29, 10%). The inheritance was recessive in six genes (DNAI1, GDF1, MMP21, MYH6, NEK8, and ZIC3) and dominant in two genes (SHH and TAB2). A homozygous pathogenic variant was found in three cases including only one case with known consanguinity. In conclusion, after removing fetuses with cytogenetic anomalies, next-generation sequencing discovered a causal variant in 12.5% of fetal cases with CHD and/or heterotaxy. Genetic counseling for future pregnancies was greatly improved. Surprisingly, unexpected consanguinity accounts for 20% of cases with identified pathogenic variants.

Biallelic PPA2 Mutations Cause Sudden Unexpected Cardiac Arrest in Infancy.

Sudden unexpected death in infancy occurs in apparently healthy infants and remains largely unexplained despite thorough investigation. The vast majority of cases are sporadic. Here we report seven individuals from three families affected by sudden and unexpected cardiac arrest between 4 and 20 months of age. Whole-exome sequencing revealed compound heterozygous missense mutations in PPA2 in affected infants of each family. PPA2 encodes the mitochondrial pyrophosphatase, which hydrolyzes inorganic pyrophosphate into two phosphates. This is an essential activity for many biosynthetic reactions and for energy metabolism of the cell. We show that deletion of the orthologous gene in yeast (ppa2Δ) compromises cell viability due to the loss of mitochondria. Expression of wild-type human PPA2, but not PPA2 containing the mutations identified in affected individuals, preserves mitochondrial function in ppa2Δ yeast. Using a regulatable (doxycycline-repressible) gene expression system, we found that the pathogenic PPA2 mutations rapidly inactivate the mitochondrial energy transducing system and prevent the maintenance of a sufficient electrical potential across the inner membrane, which explains the subsequent disappearance of mitochondria from the mutant yeast cells. Altogether these data demonstrate that PPA2 is an essential gene in yeast and that biallelic mutations in PPA2 cause a mitochondrial disease leading to sudden cardiac arrest in infants.

Genetic diversity and pathogenic variants as possible predictors of severity in a French sample of nonsyndromic heritable thoracic aortic aneurysms and dissections (nshTAAD).

PURPOSE: Heritable thoracic aortic aneurysms and dissections (hTAAD) are life-threatening complications of well-known syndromic diseases or underdiagnosed nonsyndromic heritable forms (nshTAAD). Both have an autosomal dominant transmission and are genetically heterogeneous. Our objective was to describe the relevance of molecular diagnosis in these patients and the contribution of each gene in nshTAAD. METHODS: Two hundred twenty-six consecutive nshTAAD probands, either young (<45 years) sporadic or familial cases were included. A next-generation sequencing capture panel comprising 23 known disease-causing genes was performed. RESULTS: Class 4 or 5 variants were identified in 18% of the nshTAAD probands, while class 3 variants were found in 10% of them. The yield in familial cases was greater than in sporadic cases. SMAD3 and FBN1 genes were the major disease-causing genes. Unexpectedly, no premature termination codon variant was identified in the FBN1 gene. Furthermore, we report for the first time that aortic dissection or surgery occurred significantly more often and earlier in probands with a class 4 or 5 pathogenic variant. CONCLUSION: This study indicates that genetic screening using NGS is efficient in young and familial nshTAAD. The presence of a pathogenic variant has a possible predictive value, which needs to be further investigated because it may influence care.

Bardet-Biedl syndrome: Antenatal presentation of forty-five fetuses with biallelic pathogenic variants in known Bardet-Biedl syndrome genes.

Bardet-Biedl syndrome (BBS) is an emblematic ciliopathy associated with retinal dystrophy, obesity, postaxial polydactyly, learning disabilities, hypogonadism and renal dysfunction. Before birth, enlarged/cystic kidneys as well as polydactyly are the hallmark signs of BBS to consider in absence of familial history. However, these findings are not specific to BBS, raising the problem of differential diagnoses and prognosis. Molecular diagnosis during pregnancies remains a timely challenge for this heterogeneous disease (22 known genes). We report here the largest cohort of BBS fetuses to better characterize the antenatal presentation. Prenatal ultrasound (US) and/or autopsy data from 74 fetuses with putative BBS diagnosis were collected out of which molecular diagnosis was established in 51 cases, mainly in BBS genes (45 cases) following the classical gene distribution, but also in other ciliopathy genes (6 cases). Based on this, an updated diagnostic decision tree is proposed. No genotype/phenotype correlation could be established but postaxial polydactyly (82%) and renal cysts (78%) were the most prevalent symptoms. However, autopsy revealed polydactyly that was missed by prenatal US in 55% of the cases. Polydactyly must be carefully looked for in pregnancies with apparently isolated renal anomalies in fetuses.

Familial co-occurrence of congenital heart defects follows distinct patterns.

Aims: Congenital heart defects (CHD) affect almost 1% of all live born children and the number of adults with CHD is increasing. In families where CHD has occurred previously, estimates of recurrence risk, and the type of recurring malformation are important for counselling and clinical decision-making, but the recurrence patterns in families are poorly understood. We aimed to determine recurrence patterns, by investigating the co-occurrences of CHD in 1163 families with known malformations, comprising 3080 individuals with clinically confirmed diagnosis. Methods and results: We calculated rates of concordance and discordance for 41 specific types of malformations, observing a high variability in the rates of concordance and discordance. By calculating odds ratios for each of 1640 pairs of discordant lesions observed between affected family members, we were able to identify 178 pairs of malformations that co-occurred significantly more or less often than expected in families. The data show that distinct groups of cardiac malformations co-occur in families, suggesting influence from underlying developmental mechanisms. Analysis of human and mouse susceptibility genes showed that they were shared in 19% and 20% of pairs of co-occurring discordant malformations, respectively, but none of malformations that rarely co-occur, suggesting that a significant proportion of co-occurring lesions in families is caused by overlapping susceptibility genes. Conclusion: Familial CHD follow specific patterns of recurrence, suggesting a strong influence from genetically regulated developmental mechanisms. Co-occurrence of malformations in families is caused by shared susceptibility genes.

TRPM4 non-selective cation channel variants in long QT syndrome.

BACKGROUND: Long QT syndrome (LQTS) is an inherited arrhythmic disorder characterized by prolongation of the QT interval, a risk of syncope, and sudden death. There are already a number of causal genes in LQTS, but not all LQTS patients have an identified mutation, which suggests LQTS unknown genes. METHODS: A cohort of 178 LQTS patients, with no mutations in the 3 major LQTS genes (KCNQ1, KCNH2, and SCN5A), was screened for mutations in the transient potential melastatin 4 gene (TRPM4). RESULTS: Four TRPM4 variants (2.2% of the cohort) were found to change highly conserved amino-acids and were either very rare or absent from control populations. Therefore, these four TRPM4 variants were predicted to be disease causing. Furthermore, no mutations were found in the DNA of these TRPM4 variant carriers in any of the 13 major long QT syndrome genes. Two of these variants were further studied by electrophysiology (p.Val441Met and p.Arg499Pro). Both variants showed a classical TRPM4 outward rectifying current, but the current was reduced by 61 and 90% respectively, compared to wild type TRPM4 current. CONCLUSIONS: This study supports the view that TRPM4 could account for a small percentage of LQTS patients. TRPM4 contribution to the QT interval might be multifactorial by modulating whole cell current but also, as shown in Trpm4-/- mice, by modulating cardiomyocyte proliferation. TRPM4 enlarges the subgroup of LQT genes (KCNJ2 in Andersen syndrome and CACNA1C in Timothy syndrome) known to increase the QT interval through a more complex pleiotropic effect than merely action potential alteration.

Two patients with the heterozygous R189H mutation in ACTA2 and Complex congenital heart defects expands the cardiac phenotype of multisystemic smooth muscle dysfunction syndrome.

De novo heterozygous mutations changing R179 to histidine, leucine, or cysteine in the ACTA2 gene are associated with Multisystemic Smooth Muscle Dysfunction Syndrome (MSMDS). Characteristic hallmarks of this condition, caused only by these specific ACTA2 mutations, are congenital mydriasis (mid-dilated, non-reactive pupils), a large persistent ductus arteriosus (PDA), aortic aneurysms evolving during childhood, and cerebrovascular anomalies. We describe two patients, a 3-day-old newborn and a 26-year-old woman, with this unique mutation in association with a huge PDA and an aorto-pulmonary window. In addition, one showed a coarctation of the aortic arch and the other a complete interruption of the aortic arch type A; thereby expanding the spectrum of cardiac congenital heart defect of this syndrome. Each patient displayed a huge PDA and an extra-cardiovascular phenotype consistent with MSMDS. These observations exemplify that a functional alpha 2 smooth muscle actin is necessary for proper cardiovascular organ development, and demonstrate that a very exceptional congenital heart defect (aortopulmonary window) can be caused by a mutation in a gene encoding a contractile protein of vascular smooth muscle cells. © 2017 Wiley Periodicals, Inc.

High prevalence of arrhythmic and myocardial complications in patients with cardiac glycogenosis due to PRKAG2 mutations.

AIMS: Mutations in PRKAG2, the gene encoding for the γ2 subunit of 5'-AMP-activated protein kinase (AMPK), are responsible for an autosomal dominant glycogenosis with a cardiac presentation, associating hypertrophic cardiomyopathy (HCM), ventricular pre-excitation (VPE), and progressive heart block. The aim of this study was to perform a retrospective time-to-event study of the clinical manifestations associated with PRKAG2 mutations. METHODS AND RESULTS: A cohort of 34 patients from 9 families was recruited between 2001 and 2010. DNA were sequenced on all exons and flanking sequences of the PRKAG2 gene using Sanger sequencing. Overall, four families carried the recurrent p.Arg302Gln mutation, and the five others carried private mutations among which three had never been reported. In the total cohort, at 40 years of age, the risk of developing HCM was 61%, VPE 70%, conduction block 22%, and sudden cardiac death (SCD) 20%. The global survival at 60 years of age was 66%. Thirty-two per cent of patients (N = 10) required a device implantation (5 pacemakers and 5 defibrillators) at a median age of 66 years, and two patients required heart transplant. Only one patient presented with significant skeletal muscle symptoms. No significant differences regarding the occurrence of VPE, ablation complications, or death incidence were observed between different mutations. CONCLUSION: This study of patients with PRKAG2 mutations provides a more comprehensive view of the natural history of this disease and demonstrates a high risk of cardiac complications. Early recognition of this disease appears important to allow an appropriate management.

Targeted NGS gene panel identifies mutations in RSPH1 causing primary ciliary dyskinesia and a common mechanism for ciliary central pair agenesis due to radial spoke defects.

Primary ciliary dyskinesia (PCD) is an inherited chronic respiratory obstructive disease with randomized body laterality and infertility, resulting from cilia and sperm dysmotility. PCD is characterized by clinical variability and extensive genetic heterogeneity, associated with different cilia ultrastructural defects and mutations identified in >20 genes. Next generation sequencing (NGS) technologies therefore present a promising approach for genetic diagnosis which is not yet in routine use. We developed a targeted panel-based NGS pipeline to identify mutations by sequencing of selected candidate genes in 70 genetically undefined PCD patients. This detected loss-of-function RSPH1 mutations in four individuals with isolated central pair (CP) agenesis and normal body laterality, from two unrelated families. Ultrastructural analysis in RSPH1-mutated cilia revealed transposition of peripheral outer microtubules into the 'empty' CP space, accompanied by a distinctive intermittent loss of the central pair microtubules. We find that mutations in RSPH1, RSPH4A and RSPH9, which all encode homologs of components of the 'head' structure of ciliary radial spoke complexes identified in Chlamydomonas, cause clinical phenotypes that appear to be indistinguishable except at the gene level. By high-resolution immunofluorescence we identified a loss of RSPH4A and RSPH9 along with RSPH1 from RSPH1-mutated cilia, suggesting RSPH1 mutations may result in loss of the entire spoke head structure. CP loss is seen in up to 28% of PCD cases, in whom laterality determination specified by CP-less embryonic node cilia remains undisturbed. We propose this defect could arise from instability or agenesis of the ciliary central microtubules due to loss of their normal radial spoke head tethering.

[About a case of a recurrent glandular cardiac myxoma in a child]. / À propos d'un cas de myxome cardiaque avec éléments glandulaires récidivant chez un enfant.

Primary cardiac tumors are extremely rare and mainly benign. The majority of these are myxomas (40%). Myxoma are generally sporadic tumors which occur most commonly in adult females between 30 and 40 years, and are seldom found in the paediatric population (5%). Seven percent are associated with igenetic diseases. We report the case of an eight-year-old boy presenting a recurrent glandular cardiac myxoma. In 2011, he presented a deterioration of the general state. An echocardiography highlighted a left atrial mass on the interatrial septum, with a pedicular insertion. On the microscope, it consisted of a proliferation of stellate cells isolated or clustered in rudimentary vessels in a myxoid stroma presenting haemorrhage changes. These cells expressed CD34 and calretinine. Glandular elements without atypia were clustered within the myxomatous proliferation. They expressed cytokeratin (CK) 7. Surgical resection was macroscopically complete. In 2014, the boy had a sudden neurological deficit during a football match. An echocardiography revealed a recurrence at the same location. The lesion was excised and addressed in several fragments. Classical myxoma was associated with glands without atypia. This last component expressed CKAE1/AE3 and CK7. Ki67 index of proliferation was low. The surgical reintervention was macroscopically complete. The final diagnosis was glandular cardiac myxoma. A genetic survey was conducted, showing the presence of Carney complex. This is the first description in the litterature of a recurrent glandular cardiac myxoma occuring in a child.

Antenatal description of large 4q13.2q21.23 deletion and outcomes.

BACKGROUND: 4q21 microdeletion syndrome is an emergent non-recurrent genomic disorder characterized by facial dysmorphy, progressive growth retardation, severe intellectual deficit, and absent or severely delayed speech. Deletions occur in clusters along 4q interstitial or terminal regions. 4q chromosomal aberrations are variable in type, size, and breakpoint. Genotype-phenotype correlation is a challenging task. The recurrent antenatal feature associated a posteriori with this syndrome is intrauterine growth retardation. There are very few precise antenatal descriptions of this syndrome. METHODS: We report here the first antenatal history of one of the largest deletion of this region. RESULTS: Our case harbored a 16.9 Mb deletion encompassing 135 protein coding genes including 20 OMIM morbid genes involved in neurological and cognitive abilities. Those breakpoints overlap two clusters of described microdeletion syndromes of cytogenetic band 4q13 and 4q21. CONCLUSION: From the end of the second trimester, set of call signs associated with this syndrome can be completed by: excess of amniotic fluid, mild growth retardation, short long bones, bony anomalies of the extremities, and bulging cheeks. So, emphasis should be placed on the examination of the extremities, and the face during the routine targeted prenatal ultrasound.

A human MYBPC3 mutation appearing about 10 centuries ago results in a hypertrophic cardiomyopathy with delayed onset, moderate evolution but with a risk of sudden death.

BACKGROUND: Hypertrophic Cardiomyopathy (HCM) is a genetically heterogeneous disease. One specific mutation in the MYBPC3 gene is highly prevalent in center east of France giving an opportunity to define the clinical profile of this specific mutation. METHODS: HCM probands were screened for mutation in the MYH7, MYBPC3, TNNT2 and TNNI3 genes. Carriers of the MYBPC3 IVS20-2A>G mutation were genotyped with 8 microsatellites flanking this gene. The age of this MYBPC3 mutation was inferred with the software ESTIAGE. The age at first symptom, diagnosis, first complication, first severe complication and the rate of sudden death were compared between carriers of the IVS20-2 mutation (group A) and carriers of all other mutations (group B) using time to event curves and log rank test. RESULTS: Out of 107 HCM probands, 45 had a single heterozygous mutation in one of the 4 tested sarcomeric genes including 9 patients with the MYBPC3 IVS20-2A>G mutation. The IVS20-2 mutation in these 9 patients and their 25 mutation carrier relatives was embedded in a common haplotype defined after genotyping 4 polymorphic markers on each side of the MYBPC3 gene. This result supports the hypothesis of a common ancestor. Furthermore, we evaluated that the mutation occurred about 47 generations ago, approximately at the 10th century.We then compared the clinical profile of the IVS20-2 mutation carriers (group A) and the carriers of all other mutations (group B). Age at onset of symptoms was similar in the 34 group A cases and the 73 group B cases but group A cases were diagnosed on average 15 years later (log rank test p = 0.022). Age of first complication and first severe complication was delayed in group A vs group B cases but the prevalence of sudden death and age at death was similar in both groups. CONCLUSION: A founder mutation arising at about the 10th century in the MYBPC3 gene accounts for 8.4% of all HCM in center east France and results in a cardiomyopathy starting late and evolving slowly but with an apparent risk of sudden death similar to other sarcomeric mutations.

Evidence for genetic heterogeneity in Carvajal syndrome.

Carvajal syndrome is a rare syndrome with woolly hair, palmoplantar keratosis and dilated cardiomyopathy. The inheritance of the mutation is autosomal recessive. As a causal gene, the desmoplakin gene (DSP) has so far been identified; it encodes an essential component of desmosomes, a cell-cell structure aimed at keeping cells attached to each other in tissues in which cells are often exposed to strong shear forces. Recently, familial cases of an autosomal dominant Carvajal syndrome were documented with a new feature: hypo/oligodontia. A mutation in the DSP gene was also evidenced in these latter cases. A patient was seen for cardiogenetic consultation at the University Hospital of Lyon with cardiac failure involving first degree atrioventricular block, complete left bundle branch block, non-compaction of the apex of the left ventricle and a dilated cardiomyopathy. A coronarography disclosed a complete thrombosis of the right coronary artery. At examination, he had also woolly hair, mild palmoplantar keratosis and missing teeth (essentially molars and premolars). His family history was uninformative. His DNA was screened for mutations in the DSP and plakoglobin genes but no mutation could be found. This case suggests that Carvajal syndrome with hypo/oligodontia is a heterogeneous condition in which genes other than DSP might be involved, although we cannot rule out a mutation in this gene consisting in a deletion of a single exon or a gene rearrangement.

Screening of congenital heart disease patients using multiplex ligation-dependent probe amplification: early diagnosis of syndromic patients.

Recurrent copy number variants (CNVs) are found in a significant proportion of patients with congenital heart disease (CHD) and some of these CNVs are associated with other developmental defects. In some syndromic patients, CHD may be the first presenting symptom, thus screening of patients with CHD for CNVs in specific genomic regions may lead to early diagnosis and awareness of extracardiac symptoms. We designed a multiplex ligation-dependent probe amplification (MLPA) assay specifically for screening of CHD patients. The MLPA assay allows for simultaneous analysis of CNVs in 25 genomic regions previously associated with CHD. We screened blood samples from 402 CHD patients and identified 14 rare CNVs in 13 (3.2%) patients. Five CNVs were de novo and six where inherited from a healthy parent. The MLPA screen led to early syndrome diagnosis in two of these patients. We conclude that the MLPA assay detects clinically relevant CNVs and suggest that it could be used within pediatric cardiology as a first tier screen to detect clinically relevant CNVs and identify syndromic patients at an early stage.

Ciliary beating recovery in deficient human airway epithelial cells after lentivirus ex vivo gene therapy.

Primary Ciliary Dyskinesia is a heterogeneous genetic disease that is characterized by cilia dysfunction of the epithelial cells lining the respiratory tracts, resulting in recurrent respiratory tract infections. Despite lifelong physiological therapy and antibiotics, the lungs of affected patients are progressively destroyed, leading to respiratory insufficiency. Recessive mutations in Dynein Axonemal Intermediate chain type 1 (DNAI1) gene have been described in 10% of cases of Primary Ciliary Dyskinesia. Our goal was to restore normal ciliary beating in DNAI1-deficient human airway epithelial cells. A lentiviral vector based on Simian Immunodeficiency Virus pseudotyped with Vesicular Stomatitis Virus Glycoprotein was used to transduce cultured human airway epithelial cells with a cDNA of DNAI1 driven by the Elongation Factor 1 promoter. Transcription and translation of the transduced gene were tested by RT-PCR and western blot, respectively. Human airway epithelial cells that were DNAI1-deficient due to compound heterozygous mutations, and consequently had immotile cilia and no outer dynein arm, were transduced by the lentivirus. Cilia beating was recorded and electron microscopy of the cilia was performed. Transcription and translation of the transduced DNAI1 gene were detected in human cells treated with the lentivirus. In addition, immotile cilia recovered a normal beat and outer dynein arms reappeared. We demonstrated that it is possible to obtain a normalization of ciliary beat frequency of deficient human airway epithelial cells by using a lentivirus to transduce cells with the therapeutic gene. This preliminary step constitutes a conceptual proof that is indispensable in the perspective of Primary Ciliary Dyskinesia's in vivo gene therapy. This is the first time that recovery of cilia beating is demonstrated in this disease.

Discovery of a genetic module essential for assigning left-right asymmetry in humans and ancestral vertebrates.

The vertebrate left-right axis is specified during embryogenesis by a transient organ: the left-right organizer (LRO). Species including fish, amphibians, rodents and humans deploy motile cilia in the LRO to break bilateral symmetry, while reptiles, birds, even-toed mammals and cetaceans are believed to have LROs without motile cilia. We searched for genes whose loss during vertebrate evolution follows this pattern and identified five genes encoding extracellular proteins, including a putative protease with hitherto unknown functions that we named ciliated left-right organizer metallopeptide (CIROP). Here, we show that CIROP is specifically expressed in ciliated LROs. In zebrafish and Xenopus, CIROP is required solely on the left side, downstream of the leftward flow, but upstream of DAND5, the first asymmetrically expressed gene. We further ascertained 21 human patients with loss-of-function CIROP mutations presenting with recessive situs anomalies. Our findings posit the existence of an ancestral genetic module that has twice disappeared during vertebrate evolution but remains essential for distinguishing left from right in humans.

Functional and structural basis of the nuclear localization signal in the ZIC3 zinc finger domain.

Disruptions in ZIC3 cause heterotaxy, a congenital anomaly of the left-right axis. ZIC3 encodes a nuclear protein with a zinc finger (ZF) domain that contains five tandem C2H2 ZF motifs. Missense mutations in the first ZF motif (ZF1) result in defective nuclear localization, which may underlie the pathogenesis of heterotaxy. Here we revealed the structural and functional basis of the nuclear localization signal (NLS) of ZIC3 and investigated its relationship to the defect caused by ZF1 mutation. The ZIC3 NLS was located in the ZF2 and ZF3 regions, rather than ZF1. Several basic residues interspersed throughout these regions were responsible for the nuclear localization, but R320, K337 and R350 were particularly important. NMR structure analysis revealed that ZF1-4 had a similar structure to GLI ZF, and the basic side chains of the NLS clustered together in two regions on the protein surface, similar to classical bipartite NLSs. Among the residues for the ZF1 mutations, C253 and H286 were positioned for the metal chelation, whereas W255 was positioned in the hydrophobic core formed by ZF1 and ZF2. Tryptophan 255 was a highly conserved inter-finger connector and formed part of a structural motif (tandem CXW-C-H-H) that is shared with GLI, Glis and some fungal ZF proteins. Furthermore, we found that knockdown of Karyopherin alpha1/alpha6 impaired ZIC3 nuclear localization, and physical interactions between the NLS and the nuclear import adapter proteins were disturbed by mutations in the NLS but not by W255G. These results indicate that ZIC3 is imported into the cell nucleus by the Karyopherin (Importin) system and that the impaired nuclear localization by the ZF1 mutation is not due to a direct influence on the NLS.

Supravalvular Aortic Stenosis Caused by a Familial Chromosome 7 Inversion Disrupting the ELN Gene Uncovered by Whole-Genome Sequencing.

Apparently, balanced chromosomal rearrangements usually have no phenotypic consequences for the carrier. However, in some cases, they may be associated with an abnormal phenotype. We report herein the case of a 4-year-old boy presenting with clinically isolated supravalvular aortic stenosis (SVAS). No chromosomal imbalance was detected by array CGH. The karyotype showed a balanced paracentric chromosome 7 inversion. Breakpoint characterization using paired-end whole-genome sequencing (WGS) revealed an ELN gene disruption in intron 1, accounting for the phenotype. Family study showed that the inversion was inherited, with incomplete penetrance. To our knowledge, this is the first case of a disruption of the ELN gene characterized by WGS. It contributes to refine the genotype-phenotype correlation in ELN disruption. Although this disruption is a rare etiology of SVAS, it cannot be detected by the diagnostic tests usually performed, such as array CGH or sequencing methods (Sanger, panel, or exome sequencing). With the future perspective of WGS as a diagnostic tool, it will be important to include a structural variation analysis in order to detect balanced rearrangements and gene disruption.