Clinical and molecular characterization of 40 patients with classic Ehlers--Danlos syndrome: identification of 18 COL5A1 and 2 COL5A2 novel mutations.

Classic Ehlers-Danlos syndrome (cEDS) is a rare autosomal dominant connective tissue disorder that is primarily characterized by skin hyperextensibility, abnormal wound healing/atrophic scars, and joint hypermobility. A recent study demonstrated that more than 90% of patients who satisfy all of these major criteria harbor a type V collagen (COLLV) defect. This cohort included 40 patients with cEDS who were clinically diagnosed according to the Villefranche nosology. The flowchart that was adopted for mutation detection consisted of sequencing the COL5A1 gene and, if no mutation was detected, COL5A2 analysis. In the negative patients the presence of large genomic rearrangements in COL5A1 was investigated using MLPA, and positive results were confirmed via SNP-array analysis. We report the clinical and molecular characterization of 40 patients from 28 families, consisting of 14 pediatric patients and 26 adults. A family history of cEDS was present in 9 patients. The majority of the patients fulfilled all the major diagnostic criteria for cEDS; atrophic scars were absent in 2 females, skin hyperextensibility was not detected in a male and joint hypermobility was negative in 8 patients (20% of the entire cohort). Wide inter- and intra-familial phenotypic heterogeneity was observed. We identified causal mutations with a detection rate of approximately 93%. In 25/28 probands, COL5A1 or COL5A2 mutations were detected. Twenty-one mutations were in the COL5A1 gene, 18 of which were novel (2 recurrent). Of these, 16 mutations led to nonsense-mediated mRNA decay (NMD) and to COLLV haploinsufficiency and 5 mutations were structural. Two novel COL5A2 splice mutations were detected in patients with the most severe phenotypes. The known p. (Arg312Cys) mutation in the COL1A1 gene was identified in one patient with vascular-like cEDS. Our findings highlight that the three major criteria for cEDS are useful and sufficient for cEDS clinical diagnosis in the large majority of the patients. The borderline patients for whom these criteria fail can be diagnosed when minor signs of connective tissue diseases and family history are present and when genetic testing reveals a defect in COLLV. Our data also confirm that COL5A1 and COL5A2 are the major, if not the only, genes involved in cEDS

Multiple sulfatase deficiency with neonatal manifestation.

Multiple Sulfatase Deficiency (MSD; OMIM 272200) is a rare autosomal recessive inborn error of metabolism caused by mutations in the sulfatase modifying factor 1 gene, encoding the formylglycine-generating enzyme (FGE), and resulting in tissue accumulation of sulfatides, sulphated glycosaminoglycans, sphingolipids and steroid sulfates. Less than 50 cases have been published so far. We report a new case of MSD presenting in the newborn period with hypotonia, apnoea, cyanosis and rolling eyes, hepato-splenomegaly and deafness. This patient was compound heterozygous for two so far undescribed SUMF1 mutations (c.191C > A; p.S64X and c.818A > G; p.D273G)

Gene Panel Analysis in a Large Cohort of Patients With Autosomal Dominant Polycystic Kidney Disease Allows the Identification of 80 Potentially Causative Novel Variants and the Characterization of a Complex Genetic Architecture in a Subset of Families

Introduction: Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common inherited disorders in humans and the majority of patients carry a variant in either PKD1 or PKD2. Genetic testing is increasingly required for diagnosis, prognosis, and treatment decision, but it is challenging due to segmental duplications of PKD1, genetic and allelic heterogeneity, and the presence of many variants hypomorphic or of uncertain significance. We propose an NGS-based testing strategy for molecular analysis of ADPKD and its phenocopies, validated in a diagnostic setting. Materials and Methods: Our protocol is based on high-throughput simultaneous sequencing of PKD1 and PKD2 after long range PCR of coding regions, followed by a masked reference genome alignment, and MLPA analysis. A further screening of additional 14 cystogenes was performed in negative cases. We applied this strategy to analyze 212 patients with a clinical suspicion of ADPKD. Results and Discussion: We detected causative variants (interpreted as pathogenic/likely pathogenic) in 61.3% of our index patients, and variants of uncertain clinical significance in 12.5%. The majority (88%) of genetic variants was identified in PKD1, 12% in PKD2. Among 158 distinct variants, 80 (50.6%) were previously unreported, confirming broad allelic heterogeneity. Eleven patients showed more than one variant. Segregation analysis indicated biallelic disease in five patients, digenic in one, de novo variant with unknown phase in two. Furthermore, our NGS protocol allowed the identification of two patients with somatic mosaicism, which was undetectable with Sanger sequencing. Among patients without PKD1/PKD2 variants, we identified three with possible alternative diagnosis: a patient with biallelic mutations in PKHD1, confirming the overlap between recessive and dominant PKD, and two patients with variants in ALG8 and PRKCSH, respectively. Genotype-phenotype correlations showed that patients with PKD1 variants predicted to truncate (T) the protein experienced end-stage renal disease 9 years earlier than patients with PKD1 non-truncating (NT) mutations and >13 years earlier than patients with PKD2 mutations. ADPKD-PKD1T cases showed a disease onset significantly earlier than ADPKD-PKD1NT and ADPK-PKD2, as well as a significant earlier diagnosis. These data emphasize the need to combine clinical information with genetic data to achieve useful prognostic predictions

Meta-analysis of SHANK Mutations in Autism Spectrum Disorders: A Gradient of Severity in Cognitive Impairments.

International audienceSHANK genes code for scaffold proteins located at the post-synaptic density of glutamatergic synapses. In neurons, SHANK2 and SHANK3 have a positive effect on the induction and maturation of dendritic spines, whereas SHANK1 induces the enlargement of spine heads. Mutations in SHANK genes have been associated with autism spectrum disorders (ASD), but their prevalence and clinical relevance remain to be determined. Here, we performed a new screen and a meta-analysis of SHANK copy-number and coding-sequence variants in ASD. Copy-number variants were analyzed in 5,657 patients and 19,163 controls, coding-sequence variants were ascertained in 760 to 2,147 patients and 492 to 1,090 controls (depending on the gene), and, individuals carrying de novo or truncating SHANK mutations underwent an extensive clinical investigation. Copy-number variants and truncating mutations in SHANK genes were present in ∼1% of patients with ASD: mutations in SHANK1 were rare (0.04%) and present in males with normal IQ and autism; mutations in SHANK2 were present in 0.17% of patients with ASD and mild intellectual disability; mutations in SHANK3 were present in 0.69% of patients with ASD and up to 2.12% of the cases with moderate to profound intellectual disability. In summary, mutations of the SHANK genes were detected in the whole spectrum of autism with a gradient of severity in cognitive impairment. Given the rare frequency of SHANK1 and SHANK2 deleterious mutations, the clinical relevance of these genes remains to be ascertained. In contrast, the frequency and the penetrance of SHANK3 mutations in individuals with ASD and intellectual disability-more than 1 in 50-warrant its consideration for mutation screening in clinical practice

Loss of the BMP Antagonist, SMOC-1, Causes Ophthalmo-Acromelic (Waardenburg Anophthalmia) Syndrome in Humans and Mice

Ophthalmo-acromelic syndrome (OAS), also known as Waardenburg Anophthalmia syndrome, is defined by the combination of eye malformations, most commonly bilateral anophthalmia, with post-axial oligosyndactyly. Homozygosity mapping and subsequent targeted mutation analysis of a locus on 14q24.2 identified homozygous mutations in SMOC1 (SPARC-related modular calcium binding 1) in eight unrelated families. Four of these mutations are nonsense, two frame-shift, and two missense. The missense mutations are both in the second Thyroglobulin Type-1 (Tg1) domain of the protein. The orthologous gene in the mouse, Smoc1, shows site- and stage-specific expression during eye, limb, craniofacial, and somite development. We also report a targeted pre-conditional gene-trap mutation of Smoc1 (Smoc1tm1a) that reduces mRNA to ∼10% of wild-type levels. This gene-trap results in highly penetrant hindlimb post-axial oligosyndactyly in homozygous mutant animals (Smoc1tm1a/tm1a). Eye malformations, most commonly coloboma, and cleft palate occur in a significant proportion of Smoc1tm1a/tm1a embryos and pups. Thus partial loss of Smoc-1 results in a convincing phenocopy of the human disease. SMOC-1 is one of the two mammalian paralogs of Drosophila Pentagone, an inhibitor of decapentaplegic. The orthologous gene in Xenopus laevis, Smoc-1, also functions as a Bone Morphogenic Protein (BMP) antagonist in early embryogenesis. Loss of BMP antagonism during mammalian development provides a plausible explanation for both the limb and eye phenotype in humans and mice

Spontaneous Coronary Artery Dissection in a YoungWoman With Loeys–Dietz Syndrome

We report an Italian patient with Loeys-Dietz type II syndrome and Spontaneous Coronary Artery Dissection. The present case report highlights the importance to consider the possibility of a connective-tissue disorder as potential cause of spontaneous coronary artery dissection

Recurrent triploid and dispermic conceptions in patients with NLRP7 mutations

To understand the mechanisms leading to hydatidiform mole formation in patients with NLRP7 mutations, we used a combination of various approaches to characterize five products of conception, from two patients, shown by flow cytometry to contain non-diploid cells. We demonstrate that four of these conceptions are triploid and two of them originated from fertilization with more than one sperm. We show that three of these triploid conceptions fulfill the histopathological criteria of partial hydatidiform mole and one fulfills the histopathological criteria of spontaneous abortion. Our data demonstrate that some oocytes from one patient with NLRP7 mutations are not able to prevent polyspermic fertilization and highlight the importance of using several approaches to characterize the genetic complexity of molar tissues and reproductive wastage. Altogether, our previous and current data show the association of NLRP7 mutations with several types of hydatidiform moles and with triploid spontaneous abortions. © 2011 Elsevier Ltd. All rights reserved.link_to_subscribed_fulltex

22q11.2 Distal Deletion Syndrome: Description of a New Case with Truncus Arteriosus Type 2 and Review

22q11.2 deletion syndrome is mainly characterized by conotruncal congenital heart defects, velopharyngeal insufficiency, hypocalcemia and a characteristic craniofacial appearance. The etiology in the majority of patients is a 3-Mb recurrent deletion in region 22q11.2. Nevertheless, recently some cases of infrequent deletions with various sizes have been reported with a different phenotype. We report on a patient with congenital heart disease (truncus arteriosus type 2) in whom a de novo 1.3-Mb 22q11.2 deletion was detected by array comparative genomic hybridization. The deletion described corresponds to an atypical and distal deletion which spans low copy repeat (LCR) 4 and is associated with breakpoint sites that do not correspond to known LCRs of 22q11.2. We examine the clinical phenotype of our case and compare our findings with those published in the literature. The most prevalent clinical features in this type of deletion are a history of prematurity, pre-natal and post-natal growth retardation, slight facial dysmorphic features, microcephaly and developmental delay, with a speech defect in particular. These are clearly different from those found in the classic 22q11.2 deletion syndrome, and we believe that the main differential diagnosis should be with Silver-Russel syndrome. In our case we observe the cardiac phenotype with truncus arteriosus communis usually seen in the classic 22q11.2 deletion syndrome, and so far associated with the TBX1 gene. Significantly, however, TBX1 is not included in our patient's deletion. The possible roles of a position effect or other genes are discussed