Could the MED13 mutations manifest as a Kabuki-like syndrome?

MED13-related disorder is a new neurodevelopmental disorder recently described in literature, which belongs to the group of CDK8-kinase module genes-associated conditions. It is characterized by variable intellectual disability and/or developmental delays, especially in language. Autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), eye or vision problems, hypotonia, mild congenital hearth abnormalities and dysmorphisms have been described among individuals with MED13 mutations. We report the case of a 13-year-old girl who received a previous clinical diagnosis of Kabuki syndrome (KS) without mutations in classic KS genes. After a whole exome sequencing (WES) analysis a de novo missense mutation in MED13 (c.C979T; p.Pro327Ser) was found. This variant has been once described in literature as accountable for a novel neurodevelopmental disorder. The aim of this report is to improve clinical delineation of MED13-related condition and to explore differences and similarities between KS spectrum and MED13-related disorders.

Neither hereditary periodic fever nor periodic fever, aphthae, pharingitis, adenitis: Undifferentiated periodic fever in a tertiary pediatric center.

AIM: To describe the frequency and clinical characteristics of patients with undifferentiated periodic fever (UPF) and to investigate whether a clinical classification of UPF based on the PRINTO-Eurofever score can help predicting the response to treatment and the outcome at follow-up. METHODS: Clinical and therapeutic information of patients with recurrent fever who presented at a single pediatric rheumatology center from January 2006 through April 2016 were retrospectively collected. Patients with a clinical suspicion of hereditary periodic fever (HPF) syndrome and patients with clinical picture of periodic fever, aphthae, pharingitis, adenitis (PFAPA) who were refractory to tonsillectomy underwent molecular analysis of five HPF-related genes: MEFV (NM_000243.2), MVK (NM_000431.3), TNFRSF1A (NM_001065.3), NLRP3 (NM_001079821.2), NLRP12 (NM_001277126.1). All patients who had a negative genetic result were defined as UPF and further investigated. PRINTO-Eurofever score for clinical diagnosis of HPF was calculated in all cases. RESULTS: Of the 221 patients evaluated for periodic fever, twelve subjects with a clinical picture of PFAPA who were refractory to tonsillectomy and 22 subjects with a clinical suspicion of HPF underwent genetic analysis. Twenty-three patients (10.4%) resulted negative and were classified as UPF. The median age at presentation of patients with UPF was 9.5 mo (IQR 4-24). Patients with UPF had a higher frequency of aphthae (52.2% vs 0%, P = 0.0026) and musculoskeletal pain (65.2% vs 18.2%, P = 0.0255) than patients with genetic confirmed HPF. Also, patients with UPF had a higher frequency of aphthous stomatitis (52.2% vs 10.7%, P < 0.0001), musculoskeletal pain (65.2% vs 8,0%, P < 0.0001), and abdominal pain (52.2% vs 4.8%, P < 0.0001) and a lower frequency of pharyngitis (56.6% vs 81.3%, P = 0.0127) compared with typical PFAPA in the same cohort. Twenty-one of 23 patients with UPF (91.3%) received steroids, being effective in 16; 13 (56.2%) were given colchicine, which was effective in 6. Symptoms resolution occurred in 2 patients with UPF at last follow-up. Classification according to the PRINTO-Eurofever score did not correlate with treatment response and prognosis. CONCLUSION: UPF is not a rare diagnosis among patients with periodic fever. Clinical presentation place UPF half way on a clinical spectrum between PFAPA and HPF. The PRINTO-Eurofever score is not useful to predict clinical outcome and treatment response in these patients.

Unusual splice site mutations disrupt FANCA exon 8 definition.

The pathological role of mutations that affect not conserved splicing regulatory sequences can be difficult to determine. In a patient with Fanconi anemia, we identified two unpredictable splicing mutations that act on either sides of FANCA exon 8. In patients-derived cells and in minigene splicing assay, we showed that both an apparently benign intronic c.710-5T>C transition and the nonsense c.790C>T substitution induce almost complete exon 8 skipping. Site-directed mutagenesis experiments indicated that the c.710-5T>C transition affects a polypyrimidine tract where most of the thymidines cannot be compensated by cytidines. The c.790C>T mutation located in position -3 relative to the donor site induce exon 8 skipping in an NMD-independent manner and complementation experiments with modified U1 snRNAs showed that U1 snRNP is only partially involved in the splicing defect. Our results highlight the importance of performing splicing functional assay for correct identification of disease-causing mechanism of genomic variants and provide mechanistic insights on how these two FANCA mutations affect exon 8 definition.