Fetal Description of the Pancreatic Agenesis and Holoprosencephaly Syndrome Associated to a Specific CNOT1 Variant

International audienceHoloprosencephaly (HPE) is a clinically and genetically heterogeneous disease, which can be associated with various prenatal comorbidities not always detectable on prenatal ultrasound. We report on the case of a foetus carrying a semi-lobar HPE diagnosed at ultrasound, for which a fetal autopsy and a whole exome sequencing were performed following a medical termination of pregnancy. Neuropathological examination confirmed the semi-lobar HPE and general autopsy disclosed a total pancreas agenesis. Whole exome sequencing found the CNOT1 missense c.1603C>T, p.(Arg535Cys), occurring de novo in the foetus. The same variant was previously reported in 5 unrelated children. All individuals had HPE, and 4 out of 5 presented endo- and exocrine pancreatic insufficiency or total pancreas agenesis. CNOT1 encodes a subunit of the CCRN4-NOT complex, expressed at the early stage of embryonic development. This report is the first fetal description of the phenotype associating HPE and pancreatic agenesis linked to the recurrent CNOT1 missense c.1603C>T, p.(Arg535Cys). This finding strengthens the hypothesis of a specific recurrent variant associated with a particular phenotype of HPE and pancreas agenesis. The fetal autopsy that revealed the pancreas agenesis was crucial in guiding the genetic diagnosis and enabling accurate genetic counselling

Phenotypic characterisation of SMAD4 variant carriers

International audienceBackground Both hereditary haemorrhagic telangiectasia (HHT) and juvenile polyposis syndrome (JPS) are known to be caused by SMAD4 pathogenic variants, with overlapping symptoms for both disorders in some patients. Additional connective tissue disorders have also been reported. Here, we describe carriers of SMAD4 variants followed in an HHT reference centre to further delineate the phenotype. Methods Observational study based on data collected from the Clinical Investigation for the Rendu-Osler Cohort database. Results Thirty-three participants from 15 families, out of 1114 patients with HHT, had an SMAD4 variant (3%). Regarding HHT, 26 out of 33 participants (88%) had a definite clinical diagnosis based on Curaçao criteria. Complication frequencies were as follows: epistaxis (n=27/33, 82%), cutaneous telangiectases (n=19/33, 58%), pulmonary arteriovenous malformations (n=17/32, 53%), hepatic arteriovenous malformations (AVMs) (n=7/18, 39%), digestive angiodysplasia (n=13/22, 59%). No cerebral AVMs were diagnosed. Regarding juvenile polyposis, 25 out of 31 participants (81%) met the criteria defined by Jass et al for juvenile polyposis syndrome. Seven patients (21%) had a prophylactic gastrectomy due to an extensive gastric polyposis incompatible with endoscopic follow-up, and four patients (13%) developed a digestive cancer. Regarding connective tissue disorders, 20 (61%) had at least one symptom, and 4 (15%) participants who underwent echocardiography had an aortic dilation. Conclusion We describe a large cohort of SMAD4 variant carriers in the context of HHT. Digestive complications are frequent, early and diffuse, justifying endoscopy every 2 years. The HHT phenotype, associating pulmonary and hepatic AVMs, warrants systematic screening. Connective tissue disorders broaden the phenotype associated with SMAD4 gene variants and justify systematic cardiac ultrasound and skeletal complications screening

Genetics of neural tube defects: new candidate genes and complex mode of inheritance

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Oligogenic inheritance in neural tube defects: major involvment of primary cilia, planar cell polarity and extracellular matrix genes

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Newborn Screening of Primary Carnitine Deficiency: An Overview of Worldwide Practices and Pitfalls to Define an Algorithm before Expansion of Newborn Screening in France

Primary Carnitine Deficiency (PCD) is a fatty acid oxidation disorder that will be included in the expansion of the French newborn screening (NBS) program at the beginning of 2023. This disease is of high complexity to screen, due to its pathophysiology and wide clinical spectrum. To date, few countries screen newborns for PCD and struggle with high false positive rates. Some have even removed PCD from their screening programs. To understand the risks and pitfalls of implementing PCD to the newborn screening program, we reviewed and analyzed the literature to identify hurdles and benefits from the experiences of countries already screening this inborn error of metabolism. In this study, we therefore, present the main pitfalls encountered and a worldwide overview of current practices in PCD newborn screening. In addition, we address the optimized screening algorithm that has been determined in France for the implementation of this new condition

Skraban-Deardorff Syndrome: six new cases of WDR26-related disease and expansion of the clinical phenotype

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Skraban-Deardorff Syndrome: six new cases of WDR26-related disease and expansion of the clinical phenotype

International audienc

Skraban-Deardorff Syndrome: six new cases of WDR26-related disease and expansion of the clinical phenotype

International audienc

Skraban-Deardorff syndrome: six new cases of WDR26-related disease and expansion of the clinical phenotype

International audienceSkraban-Deardorff syndrome (a disease related to variations in the WDR26 gene; OMIM #617616) was first described in a cohort of 15 individuals in 2017. The syndrome comprises intellectual deficiency, severe speech impairment, ataxic gait, seizures, mild hypotonia with feeding difficulties during infancy, and dysmorphic features. Here, we report on six novel heterozygous de novo pathogenic variants in WDR26 in six probands. The patients’ phenotypes were consistent with original publication. One patient displayed marked hypotonia with an abnormal muscle biopsy; this finding warrants further investigation. Gait must be closely monitored, in order to highlight any musculoskeletal or neurological abnormalities and prompt further examinations. Speech therapy and alternative communication methods should be initiated early in the clinical follow-up, in order to improve language and oral eating and drinking

The EPIGENE network: A French initiative to harmonize and improve the nationwide diagnosis of monogenic epilepsies

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