Bi-allelic variants in IPO8 cause a connective tissue disorder associated with cardiovascular defects, skeletal abnormalities, and immune dysregulation.

Dysregulated transforming growth factor TGF-ß signaling underlies the pathogenesis of genetic disorders affecting the connective tissue such as Loeys-Dietz syndrome. Here, we report 12 individuals with bi-allelic loss-of-function variants in IPO8 who presented with a syndromic association characterized by cardio-vascular anomalies, joint hyperlaxity, and various degree of dysmorphic features and developmental delay as well as immune dysregulation; the individuals were from nine unrelated families. Importin 8 belongs to the karyopherin family of nuclear transport receptors and was previously shown to mediate TGF-ß-dependent SMADs trafficking to the nucleus in vitro. The important in vivo role of IPO8 in pSMAD nuclear translocation was demonstrated by CRISPR/Cas9-mediated inactivation in zebrafish. Consistent with IPO8's role in BMP/TGF-ß signaling, ipo8-/- zebrafish presented mild to severe dorso-ventral patterning defects during early embryonic development. Moreover, ipo8-/- zebrafish displayed severe cardiovascular and skeletal defects that mirrored the human phenotype. Our work thus provides evidence that IPO8 plays a critical and non-redundant role in TGF-ß signaling during development and reinforces the existing link between TGF-ß signaling and connective tissue defects.

Risk factors for surgery in stricturing small bowel Crohn's disease: A retrospective cohort study from the GETAID pédiatrique.

OBJECTIVES: Previous studies have shown rates of surgical resection of up to 41% in stricturing pediatric Crohn's disease (CD). In this retrospective multicenter study, our aims were to identify clinical risk factors and magnetic resonance enterography (MRE) features of small bowel strictures associated with surgery. METHODS: Pediatric patients with symptomatic stricturing small bowel CD (defined as obstructive symptoms or proximal dilatation on MRE) confirmed by MRE between 2010 and 2020 were recruited from 12 French tertiary hospitals. Patient characteristics were compared by surgical outcome multivariable Cox regression. RESULTS: Fifty-six patients (61% boys) aged 12.2 ± 2.7 years at diagnosis of CD were included. Median duration of CD before diagnosis of stricture was 11.7 months (interquartile range [IQR]: 25-75: 1.2-29.9). Nineteen (34%) patients had stricturing phenotype (B2) at baseline. Treatments received  before stricture diagnosis included MODULEN-IBD (n = 31), corticosteroids (n = 35), antibiotics (n = 10), anti-TNF (n = 27), immunosuppressants (n = 28). Thirty-six patients (64%) required surgery, within 4.8 months (IQR: 25-75: 1.8-17.3) after stricture diagnosis. Parameters associated with surgical resection were antibiotic exposure before stricture diagnosis (adjusted odds ratio [aOR]: 15.62 [3.35-72.73], p = 0.0005), Crohn's disease obstructive symptoms score (CDOS) > 4 (aOR: 3.04 [1.15-8.03], p = 0.02) and dilation proximal to stricture >28 mm (aOR: 3.62 [1.17-11.20], p = 0.03). CONCLUSION: In this study, antibiotic treatment before stricture diagnosis, intensity of obstructive symptoms, and diameter of dilation proximal to small bowel stricture on MRE were associated with risk for surgical resection.

Comparison of Endoscopic Dilatation and Heller's Myotomy for Treating Esophageal Achalasia in Children: A Multicenter Study.

OBJECTIVE: To compare the efficacy of, and complications from, the 2 main treatments for achalasia: endoscopic dilatation and surgical cardiomyotomy (Heller's myotomy). STUDY DESIGN: We retrospectively collected data on children treated for achalasia over an 11-year period from 8 tertiary pediatric centers. A line of treatment was defined as performing either Heller's myotomy or 1-3 sessions of endoscopy dilatation over 3 months. Treatment success was a priori defined as clinical improvement and no need for new treatment. RESULTS: Ninety-seven children (median age, 12 years; 57% boys) were included. The median time to diagnosis was 10.5 months, and the median follow-up period was 27 months. Thirty-seven children were treated by Heller's myotomy and 60 by endoscopy dilatation as the first-line treatment. After adjustment for potentially confounding factors, Heller's myotomy was significantly more successful than endoscopy dilatation (hazard ratio, 3.93 [1.74; 8.88]; P = .001), with a median survival without failure of 49 and 7 months, respectively, and with no significant difference in the occurrence of complications (35.2% for Heller's myotomy, 29.7% for endoscopy dilatation, P = .56). Hydrostatic dilatation was as successful as pneumatic dilatation (hazard ratio, 1.35 [0.56; 3.23]; P = .50). CONCLUSIONS: Heller's myotomy is more successful than endoscopy dilatation, with no significant difference in the occurrence of serious complications. This raises the potential role of peroral endoscopic myotomy as an alternative treatment to Heller's myotomy.

Clinical Remission and Psychological Management are Major Issues for the Quality of Life in Pediatric Crohn Disease.

OBJECTIVES: Crohn disease (CD) can affect patient's quality of life (QOL) with physical, social, and psychological impacts. This study aimed to investigate the QOL of children with CD and its relationship with patient and disease characteristics. METHODS: Children ages from 10 to 17 years with diagnosed CD for more than 6 months were eligible to this cross-sectional study conducted in 35 French pediatric centers. QOL was assessed by the IMPACT-III questionnaire. Patient and disease characteristics were collected. RESULTS: A total of 218 children (42% of girls) were included at a median age of 14 years (interquartile range [IQR]: 13--16). Median duration of CD was 3.2 years (IQR: 1.7-5.1) and 63% of children were in clinical remission assessed by wPCDAI. Total IMPACT-III score was 62.8 (±11.0). The lowest score was in "emotional functioning" subdomain (mean: 42.8 ±â€Š11.2). Clinical remission was the main independent factor associated with QOL of children with CD (5.74 points higher compared with those "with active disease", 95% confidence interval [CI] 2.77--8.70, P < 0.001). Age of patient at the evaluation was found negatively correlated with QOL (-0.76 per year, 95% CI: -1.47 to -0.06, P = 0.009). Presence of psychological disorders was associated with a lower QOL (-9.6 points lower to those without, 95% CI: -13.34 to -5.86, P < 0.0001). Total IMPACT-III and its subdomains scores were not related to sex, disease duration, or treatments. CONCLUSIONS: These results not only confirm that clinical remission is a major issue for the QOL of patients, but also highlights the importance of psychological care.

Predictors of the Performance of Early Antireflux Surgery in Esophageal Atresia.

OBJECTIVE: To identify predictors of and factors associated with the performance of antireflux surgery during the first year of life in children born with esophageal atresia. STUDY DESIGN: All patients were included in a French registry for esophageal atresia. All 38 multidisciplinary French centers completed questionnaires about perinatal characteristics and one-year outcome for children born with esophageal atresia. RESULTS: Of 835 infants with esophageal atresia born in France from 2010 to 2014, 682 patients, excluding those with long-gap esophageal atresia, were included. Three patients had type I, 669 had type III, and 10 had type IV esophageal atresia. Fifty-three children (7.8%) received fundoplication during the first year of life. The median age at the time of the end-to-end esophageal anastomosis was 1.1 day (range 0-15). Multivariate analysis identified three perioperative factors that predicted the need for early antireflux surgery: anastomotic tension (P = .004), associated malformations (P = .019), and low birth weight (P = .018). Six other factors, measured during the first year of life, were associated with the need for antireflux surgery: gastroesophageal reflux (P < .001), anastomotic stricture (P < .001), gastrostomy (P < .001), acute life-threatening event (P = .002), respiratory complications (P = .045), and poor nutritional status (P < .001). CONCLUSIONS: Gastroesophageal reflux disease, low birth weight, poor nutrition, and surgical anastomosis difficulties predicted the performance of antireflux surgery in the first year of life in infants with esophageal atresia.

Bilateral uveitis and macular edema induced by Nivolumab: a case report.

BACKGROUND: Nivolumab is a fully human antibody which is routinely used at first therapy for metastatic melanoma. Usually, side effects are immune-related adverse events. We report a case of a man who developed bilateral anterior uveitis and macular serous retinal detachment during nivolumab treatment for metastatic melanoma. CASE PRESENTATION: A man on nivolumab treatment for a leg melanoma with duodenal and lymph nodes metastases developed a sudden bilateral visual acuity impairment and bilateral non-painfull redness eyes several days after the third infusion. The clinical examination showed a significant decreased of the visual acuity. Slit lamp examination revealed the presence of bilateral granulomatous keratic precipitates, anterior chamber cells +++, bilateral synechiae, bilateral papilledema and macular edema associated with serous retinal detachment in the left eye. The anti-Programmed cells Death-1 was stopped and a topical corticosteroid treatment was administrated. After 8 days of topical corticosteroid treatment visual acuity was worsening with similar optical coherence tomography examination. An oral corticosteroid treatment was started. Evolution was favorable with a decrease of ocular inflammation and a complete visual acuity recovery after 3 weeks. Nivolumab was re-initiated. CONCLUSIONS: This is the second clinical report of bilateral anterior uveitis associated with macular serous retinal detachment related to anti-PD-1 treatment, and the first with nivolumab. Cases of uveitis were reported several times. Although rare, ophthalmologic manifestations that are rapidly recognized and adequately managed can be treated.

Prevalence of Barrett Esophagus in Adolescents and Young Adults With Esophageal Atresia.

OBJECTIVE: To study the prevalence of Barrett esophagus (BE) (gastric and/or intestinal metaplasia) in adolescents treated for esophageal atresia (EA). SUMMARY OF BACKGROUND DATA: EA patients are at high risk of BE. METHODS: This multicenter prospective study included EA patients aged 15 to 19 years. All eligible patients were proposed an upper endoscopy with multistaged esophageal biopsies under general anesthesia. Histological suspicion of metaplasia was confirmed centrally. RESULTS: One hundred twenty patients [mean age, 16.5 years (±1.4)] were included; 70% had been treated for gastroesophageal reflux disease (GERD) during infancy. At evaluation, 8% were undernourished, 41% had received antireflux surgery, and 41% presented with GERD symptoms, although only 28% were receiving medical treatment. Esophagitis was found at endoscopy in 34% and confirmed at histology in 67%. BE was suspected after endoscopy in 37% and was confirmed by histology for 43% of patients (50 gastric and 1 intestinal metaplasia). No endoscopic or histological anomalies were found at the anastomosis site. BE was not significantly related to clinical symptoms. In multivariate analysis, BE was associated with EA without fistula (P = 0.03), previous multiple antireflux surgery (P = 0.04), esophageal dilation (P = 0.04), suspicion of BE at endoscopy (P < 0.001), and histological esophagitis (P = 0.02). CONCLUSIONS: Patients with EA are at high risk of persistent GERD and BE. The development of BE is related to GERD history. Long-term systematic follow-up of the esophageal mucosa including multistaged biopsies is required, even in asymptomatic patients. (NCT02495051).

Qualitative analysis of bulk-heterojunction solar cells without device fabrication: an elegant and contactless method.

The enormous synthetic efforts on novel solar cell materials require a reliable and fast technique for the rapid screening of novel donor/acceptor combinations in order to quickly and reliably estimate their optimized parameters. Here, we report the applicability of such a versatile and fast evaluation technique for bulk heterojunction (BHJ) organic photovoltaics (OPV) by utilizing a steady-state photoluminescence (PL) method confirmed by electroluminescence (EL) measurements. A strong relation has been observed between the residual singlet emission and the charge transfer state emission in the blend. Using this relation, a figure of merit (FOM) is defined from photoluminescence and also electroluminescence measurements for qualitative analysis and shown to precisely anticipate the optimized blend parameters of bulk heterojunction films. Photoluminescence allows contactless evaluation of the photoactive layer and can be used to predict the optimized conditions for the best polymer-fullerene combination. Most interestingly, the contactless, PL-based FOM method has the potential to be integrated as a fast and reliable inline tool for quality control and material optimization.

Nutritional status at age 1 year in patients born with esophageal atresia: A population-based, prospective cohort study.

Objective: Despite recent progress in caring for patients born with esophageal atresia (EA), undernutrition and stunting remain common. Our study objective was to assess nutritional status in the first year after birth with EA and to identify factors associated with growth failure. Study design: We conducted a population-based study of all infants born in France with EA between 2010 and 2016. Through the national EA register, we collected prenatal to 1 year follow-up data. We used body mass index and length-for-age ratio Z scores to define patients who were undernourished and stunted, respectively. Factors with P < 0.20 in univariate analyses were retained in a logistic regression model. Results: Among 1,154 patients born with EA, body mass index and length-for-age ratio Z scores at 1 year were available for about 61%. Among these, 15.2% were undernourished and 19% were stunted at the age of 1 year. There was no significant catch-up between ages 6 months and 1 year. Patients born preterm (41%), small for gestational age (17%), or with associated abnormalities (55%) were at higher risk of undernutrition and stunting at age 1 year (P < 0.05). Neither EA type nor surgical treatment was associated with growth failure. Conclusion: Undernutrition and stunting are common during the first year after birth in patients born with EA. These outcomes are significantly influenced by early factors, regardless of EA type or surgical management. Identifying high-risk patient groups with EA (i.e., those born preterm, small for gestational age, and/or with associated abnormalities) may guide early nutritional support strategies.

Management of Central Venous Catheters in Children and Adults on Home Parenteral Nutrition: A French Survey of Current Practice.

Although central venous catheter (CVC)-related thrombosis (CRT) is a severe complication of home parenteral nutrition (HPN), the amount and quality of data in the diagnosis and management of CRT remain low. We aimed to describe current practices regarding CVC management in French adult and pediatric HPN centers, with a focus on CVC obstruction and CRT. Current practices regarding CVC management in patients on HPN were collected by an online-based cross-sectional survey sent to expert physicians of French HPN centers. We compared these practices to published guidelines and searched for differences between pediatric and adult HPN centers' practices. Finally, we examined the heterogeneity of practices in both pediatric and adult HPN centers. The survey was completed by 34 centers, including 21 pediatric and 13 adult centers. We found a considerable heterogeneity, especially in the responses of pediatric centers. On some points, the centers' responses differed from the current guidelines. We also found significant differences between practices in adult and pediatric centers. We conclude that the management of CVC and CRT in patients on HPN is a serious and complex situation for which there is significant heterogeneity between HPN centers. These findings highlight the need for more well-designed clinical trials in this field.

Novel mutations in TTC37 associated with tricho-hepato-enteric syndrome.

The Tricho-Hepato-Enteric (THE) syndrome is an autosomal recessive condition marked by early and intractable diarrhea, hair abnormalities, and immune defects. Mutations in TTC37, which encodes the putative protein Thespin, have recently been associated with THE syndrome. In this article, we extend the pattern of TTC37 mutations by the description of 11 novel mutations in 9 patients with a typical THE syndrome. The mutations were spread along the gene sequence, none of themrecurrent. Different types of mutation were observed: frameshift mutations, splice-site altering mutations, or missense mutations, most of them leading to the creation of a premature stop codon. Concurrently, we investigated the pattern of TTC37 expression in a panel of normal human tissues and showed that this gene is widely expressed, with high levels in vascular tissues, lymph node, pituitary, lung, and intestine. In contrast, TTC37 is not expressed in the liver, an organ that is not consistently affected in THE syndrome. Last, we suggested a model for the putative structure of the unknown Thespin protein.

Decidual soluble factors participate in the control of HIV-1 infection at the maternofetal interface.

BACKGROUND: Maternofetal transmission (MFT) of HIV-1 is relatively rare during the first trimester of pregnancy despite the permissivity of placental cells for cell-to-cell HIV-1 infection. Invasive placental cells interact directly with decidual cells of the uterine mucosa during the first months of pregnancy, but the role of the decidua in the control of HIV-1 transmission is unknown. RESULTS: We found that decidual mononuclear cells naturally produce low levels of IL-10, IL-12, IL-15, TNF-α, IFN-α, IFN-γ and CXCL-12 (SDF-1), and large amounts of CCL-2 (MCP1), CCL-3 (MIP-1α), CCL-4 (MIP-1ß), CCL-5 (Rantes), CXCL-10 (IP-10), IL-6 and IL-8. CCL-3 and CCL-4 levels were significantly upregulated by in vitro infection with R5 HIV-1 but not X4. Decidual CD14+ antigen presenting cells were the main CCL-3 and CCL-4 producers among decidual leukocytes. R5 and X4 HIV-1 infection was inhibited by decidual cell culture supernatants in vitro. Using HIV-1 pseudotypes, we found that inhibition of the HIV-1 entry step was inhibited by decidual soluble factors. CONCLUSION: Our findings show that decidual innate immunity (soluble factors) is involved in the control of HIV-1 infection at the maternofetal interface. The decidua could thus serve as a mucosal model for identifying correlates of protection against HIV-1 infection.

Reduced expression of FOXP3 and regulatory T-cell function in severe forms of early-onset autoimmune enteropathy.

BACKGROUND & AIMS: Little is known about the pathophysiology of early onset forms of autoimmune enteropathy (AIE). AIE has been associated with mutations in FOXP3-a transcription factor that controls regulatory T-cell development and function. We analyzed the molecular basis of neonatal or early postnatal AIE using clinical, genetic, and functional immunological studies. METHODS: Gastroenterological and immunological features were analyzed in 9 boys and 2 girls with AIE that began within the first 5 months of life. FOXP3 and IL2RA were genotyped in peripheral blood monocytes. FOXP3 messenger RNA and protein expression were analyzed using reverse-transcription polymerase chain reaction, flow cytometry, and confocal immunofluorescence of CD4(+) T cells. Regulatory T-cell function (CD4(+)CD25(+)) was assayed in coculture systems. RESULTS: AIE associated with extraintestinal autoimmunity was severe and life-threatening; all patients required total parenteral nutrition. Regulatory T cells from 7 patients had altered function and FOXP3 mutations that resulted in lost or reduced FOXP3 protein expression; 2 infants had reduced regulatory T-cell activity and reduced levels of FOXP3 protein, although we did not detect mutations in FOXP3 coding region, poly-A site, or promoter region (called FOXP3-dependent AIE). Two patients had a normal number of regulatory T cells that expressed normal levels of FOXP3 protein and normal regulatory activity in in vitro coculture assays (called FOXP3-independent AIE). No mutations in IL2RA were found. CONCLUSIONS: Most cases of AIE are associated with alterations in regulatory T-cell function; some, but not all, cases have mutations that affect FOXP3 expression levels. Further studies are needed to identify mechanisms of AIE pathogenesis.

Pediatric Home Parenteral Nutrition in France: A six years national survey.

BACKGROUND AND AIMS: Home Parenteral Nutrition (HPN) is the cornerstone management for children suffering from chronic intestinal failure (CIF). In France, HPN is organized from a network of 7 certified centers located in University Hospitals spread across the national territory. This study aims to review the data involving children on HPN over a 6-years period in France to outline the global and continuous improvement in care. PATIENTS AND METHODS: This cross-sectional study included all children enrolled in any of the 7 French HPN certified centers from January 1st, 2014 to December 31st, 2019. Data was recorded from annual databases provided by each center regarding: age at inclusion, indication and duration of HPN, type of intravenous lipid emulsion (ILE), outcome [PN weaning off, transfer to adult center, death, intestinal transplantation (ITx)], rate of catheter-related bloodstream infections (CRSBIs) for 1000 days of HPN, Taurolidine lock procedure (TLP) use and prevalence of cholestasis defined as conjugated bilirubin ≥20 µmol/l. RESULTS: The number of patients increased by 43.6% from 268 in 2014 to 385 in 2019. According to the year of follow up, the indications for HPN were short bowel syndrome (SBS) (42.3-46.6%), congenital enteropathies (CE) (18.5-22.8%), chronic intestinal pseudo-obstruction syndrome (CIPOS) (13.0-16.3%), long segment Hirschsprung's disease (LSHD) (9.7-13.3%), Crohn's disease (CD) (1.6-2.6%) and other non-primary digestive diseases (NPDD) such as immune deficiency, cancer or metabolic disease (4.0-9.2%). The median age at discharge on HPN decreased from 11.7 months in 2014 to 8.3 months in 2019 (p < .001). By December 31st, 2019, 44.8% of children had left the HPN program after a median duration ranging between 39.9 and 66.4 months. Among these patients, 192 (74.2%) were weaned off PN (94.7% SBS), 41 (15.8%) were transferred to adult centers for CIPOS (42%), SBS (31%) or CE (27%), 21 died (8.1%) - mostly in relation to cancer or immune deficiency - and 5 were transplanted (1.9%): 4 underwent combined liver-intestine transplantation for LSHD (n = 2), SBS, CE and one multivisceral Tx for CIPOS. The use of a composite fish-oil based ILE increased from 67.4% in 2014 to 88.3% in 2019 (p < 0.001). CRBSIs dropped from 1.04 CRSBIs per 1000 days HPN in 2014 to 0.61 in 2019 (p < 0.001) while meantime, the percentage of children receiving TLP increased from 29.4% to 63.0% (p < 0.001). The prevalence of cholestasis (conjugated bilirubin ≥ 20 µmol/l) was low and stable between 4.1 and 5.9% of children during the study period. CONCLUSION: In France, the number of children enrolled in a HPN program continuously increased over a 6 years period. SBS is the leading cause of CIF requiring HPN. The rate of CRBSIs dropped dramatically as the use of TLP increased. Mortality rate was low and mainly in relation to the underlying disease (cancer, immune deficiency). Cholestasis and intestinal Tx remained very rare.

Functional abdominal pain disorders and patient- and parent-reported outcomes in children with inflammatory bowel disease in remission.

BACKGROUND: Chronic abdominal pain occurs frequently in pediatric patients with inflammatory bowel disease (IBD) in remission. AIMS: To assess the prevalence and factors associated with Functional Abdominal Pain Disorders among IBD children in remission (IBD-FAPD). METHODS: Patients with IBD for > 1 year, in clinical remission for ≥ 3 months were recruited from a National IBD network. IBD-FAPDs were assessed using the Rome III questionnaire criteria. Patient- or parent- reported outcomes were assessed. RESULTS: Among 102 included patients, 57 (56%) were boys, mean age (DS) was 15.0 (± 2.0) years and 75 (74%) had Crohn's disease. Twenty-two patients (22%) had at least one Functional Gastrointestinal Disorder among which 17 had at least one IBD-FAPD. Past severity of disease or treatments received and level of remission were not significantly associated with IBD-FAPD. Patients with IBD-FAPD reported more fatigue (peds-FACIT-F: 35.9 ± 9.8 vs. 43.0 ± 6.9, p = 0.01) and a lower HR-QoL (IMPACT III: 76.5 ± 9.6 vs. 81.6 ± 9.2, p = 0.04) than patients without FAPD, and their parents had higher levels of State and Trait anxiety than the other parents. CONCLUSIONS: Prevalence of IBD-FAPD was 17%. IBD-FAPD was not associated with past severity of disease, but with fatigue and lower HR-QoL.

Primary cutaneous marginal zone lymphoma as a complication of radiation therapy: Case report and review.

BACKGROUND: The occurrence of primary cutaneous B-cell lymphoma at the site of radiation therapy is exceptional. We report herein the case of a primary cutaneous marginal zone lymphoma arising at the site of radiotherapy for breast cancer. METHODS/RESULTS: A seventy-year-old woman was diagnosed in 2005 with an invasive ductal carcinoma of the left breast, which was treated with surgery, adjuvant chemotherapy, and radiation therapy. Three years later she developed several cutaneous nodules on her left breast, followed by similar lesions on her back. Histologic, immunohistochemistry, and molecular findings were consistent with the diagnosis of cutaneous marginal zone lymphoma. Physical examination was otherwise negative, as well as mammography, total body CT, bone marrow biopsy, and Borrelia serology. CONCLUSIONS: To our knowledge, this is the first published case of primary cutaneous marginal zone lymphoma occurring at the site of radiotherapy. Cutaneous surveillance is proposed from the first year after irradiation in order to detect new primary malignancies, including this rare cutaneous neoplasm.

Optimization of biologics to reduce treatment failure in inflammatory bowel diseases.

Moderate to severe inflammatory bowel disease patients can fail to respond to conventional therapy and/or to biologic treatment. In the era of TNFα antagonists and other non-anti-TNF biologic drugs, it is important to review the literature on biologic treatment failure, which could be defined as primary non-response, secondary loss of response and intolerance. Therapeutic drug monitoring (TDM), that is, drug trough level and antidrug antibodies, should enable to determine the mechanisms of treatment failure and to optimize drug efficacy. There is a consensus on reactive TDM at the time of loss of response. Proactive TDM could be of interest during induction and/or maintenance, but randomized controlled trials are required.

Exclusion of EGFR, HRAS, DSP, JUP, CTNNB1, PLEC1, and EPPK1 as functional candidate genes in 7 families with syndromic diarrhoea.

Syndromic diarrhoea (SD) is a rare disease associating intractable diarrhoea and hair abnormalities. In an attempt to identify the gene causative for SD, we studied several functional candidate genes, based on their implication in overlapping phenotypes in mice (EGFR) or in humans (HRAS, JUP, DSP EPPK1, PLEC1, and CTNNB1) in 8 patients affected by SD. Except for EGFR and HRAS, all selected genes encode for cell adhesion proteins. Using direct sequencing or linkage analysis, we excluded all of the candidate genes as the disease-causing gene in our group of patients; however, the hypothesis of intercellular junctions defect in SD remains seductive.