Introduction: Fanconi anemia (FA) is a genome instability condition that drives somatic mosaicism in up to 25% of all patients, a phenomenon now acknowledged as a good prognostic factor. Herein, we describe the case of P1, a FA proband carrying a splicing variant, molecularly compensated by a de novo insertion.Methods and Results: Targeted next-generation sequencing on P1’s peripheral blood DNA detected the known FANCA c.2778 + 83C > G intronic mutation and suggested the presence of a large deletion on the other allele, which was then assessed by MLPA and RT-PCR. To determine the c.2778 + 83C > G splicing effect, we performed a RT-PCR on P1’s lymphoblastoid cell line (LCL) and on the LCL of another patient (P2) carrying the same variant. Although we confirmed the expected alternative spliced form with a partial intronic retention in P2, we detected no aberrant products in P1’s sample. Sequencing of P1’s LCL DNA allowed identification of the de novo c.2778 + 86insT variant, predicted to compensate 2778 + 83C > G impact. Albeit not found in P1’s bone marrow (BM) DNA, c.2778 + 86insT was detected in a second P1’s LCL established afterward, suggesting its occurrence at a low level in vivo. Minigene assay recapitulated the c.2778 + 83C > G effect on splicing and the compensatory role of c.2778 + 86insT in re-establishing the physiological mechanism. Accordingly, P1’s LCL under mitomycin C selection preserved the FA pathway activity in terms of FANCD2 monoubiquitination and cell survival.Discussion: Our findings prove the role of c.2778 + 86insT as a second-site variant capable of rescuing c.2778 + 83C > G pathogenicity in vitro, which might contribute to a slow hematopoietic deterioration and a mild hematologic evolution.

Background: Despite consolidated guidelines, the clinical diagnosis and prognosis of cystic fibrosis (CF) is still challenging mainly because of the extensive phenotypic heterogeneity and the high number of CFTR variants, including their combinations as complex alleles.Results: We report a family with a complicated syndromic phenotype, which led to the suspicion not only of CF, but of a dominantly inherited skeletal dysplasia (SD). Whereas the molecular basis of the SD was not clarified, segregation analysis was central to make a correct molecular diagnosis of CF, as it allowed to identify three CFTR variants encompassing two known maternal mutations and a novel paternal microdeletion.Conclusion: This case well illustrates possible pitfalls in the clinical and molecular diagnosis of CF; presence of complex phenotypes deflecting clinicians from appropriate CF recognition, and/or identification of two mutations assumed to be in trans but with an unconfirmed status, which underline the importance of an in‐depth molecular CFTR analysis.

Intestinal anti-endomysium antibodies are a specific marker of celiac disease. The diagnostic accuracy of this marker seems high in pediatric patients and has not yet been investigated in adults, so the aim of this prospective multicentric study was to evaluate the specificity and sensitivity of this marker in childhood and adulthood. Pediatric and adult patients undergoing intestinal endoscopy for any intestinal condition were enrolled. Serological celiac disease markers and HLA type were evaluated in all patients. Intestinal biopsies were analyzed for standard histology and for intestinal anti-endomysium antibodies with biopsy culture assay. In this study, 291 patients (145 adults and 146 children) were included. In the adult population, 34 were diagnosed with celiac disease, 105 were controls, and, in 6, celiac disease was not confirmed. In the pediatric population, 77 were diagnosed with celiac disease, 57 were controls, and, in 12, celiac disease was not confirmed. High diagnostic sensitivity and specificity of intestinal anti-endomysium antibodies were confirmed in children and additionally proven in adults. To conclude, we can affirm that intestinal anti-endomysium antibodies can be detected with high diagnostic accuracy in both children and adults. The implementation of this marker in the diagnostic work-up would help clinicians to correctly identify celiac disease.

Background/Objectives: A lifelong gluten-free diet (GFD) is the only treatment for celiac disease (CD). However, current methods for monitoring GFD adherence do not accurately assess gluten exposure. Stool detection of gluten immunogenic peptides (GIP) may provide an objective tool for detecting recent gluten exposure. The aim of this study was to evaluate stool GIP detection, compared with serology and the validated Biagi dietary questionnaire, for monitoring GFD adherence in children with CD. Methods: In this prospective multicenter study, pediatric patients with CD on a GFD for at least 1 year were enrolled. Serum and stool samples were collected on the same day to assess serum anti-transglutaminase (TTG) and anti-endomysium (EMA) antibodies and stool GIP. Patients also completed the Biagi dietary questionnaire. Results: Forty-one pediatric patients with CD on a GFD for a median of 6.5 years were enrolled. Serum TTG and/or EMA were positive in 8/41 patients (19.5%), Biagi questionnaire identified 8/41 patients (19.5%) as non-adherent, whereas stool GIP was positive in 17/41 (41.5%). Combining serology with the dietary questionnaire increased the proportion of non-adherent patients to 34%. Adding stool GIP detection increased this proportion to 51% and 46% when combined with serology or the dietary questionnaire, respectively. Overall, 23/41 patients (56%) showed evidence of gluten exposure when positivity in at least one of the three methods was considered. Conclusions: A high rate of recent gluten exposure was detected in children with CD on a long-term GFD. Stool GIP detection may provide complementary information to conventional methods for monitoring GFD adherence and may help identify patients requiring further dietary assessment or intervention.