Outcome in patients with cystic fibrosis liver disease

AbstractBackgroundLiver disease is an important complication in CF.AimsTo determine if CFLD is a risk factor for mortality in CF, and which baseline characteristics predict all-cause mortality.MethodsIrish children with CFLD, and their age and gender matched controls were enrolled at baseline and reviewed after 10years to determine which characteristics predict mortality.Results72/84 (85.71%) participants were followed, (mean age Cases 21.71yrs SD 6.5, CF controls 23.62 SD 5.6, 22 (61%) males), with no difference in duration of follow-up. Nineteen participants (26.4%) died, 38.9% (14/36) with CFLD and 13.89% (5/36) CF controls (Odds Ratio (OR) 3.94 95% CI:1.23–12.56 p=0.005). In logistic regression, liver disease (OR 4.28 95% CI 1.07–17.16) female gender (OR 12.25 95% CI 2.37–63.24), reduced pulmonary function, (OR 5.11 95% CI 1.09–23.81) were each independent risk factors for mortality in CF.ConclusionsLiver disease is an independent risk factor for mortality in CF

De novo intrachromosomal gene conversion from OPN1MW to OPN1LW in the male germline results in Blue Cone Monochromacy

X-linked cone dysfunction disorders such as Blue Cone Monochromacy and X-linked Cone Dystrophy are characterized by complete loss (of) or reduced L- and M- cone function due to defects in the OPN1LW/OPN1MW gene cluster. Here we investigated 24 affected males from 16 families with either a structurally intact gene cluster or at least one intact single (hybrid) gene but harbouring rare combinations of common SNPs in exon 3 in single or multiple OPN1LW and OPN1MW gene copies. We assessed twelve different OPN1LW/MW exon 3 haplotypes by semi-quantitative minigene splicing assay. Nine haplotypes resulted in aberrant splicing of ≥20% of transcripts including the known pathogenic haplotypes (i.e. ‘LIAVA’, ‘LVAVA’) with absent or minute amounts of correctly spliced transcripts, respectively. De novo formation of the ‘LIAVA’ haplotype derived from an ancestral less deleterious ‘LIAVS’ haplotype was observed in one family with strikingly different phenotypes among affected family members. We could establish intrachromosomal gene conversion in the male germline as underlying mechanism. Gene conversion in the OPN1LW/OPN1MW genes has been postulated, however, we are first to demonstrate a de novo gene conversion within the lineage of a pedigree

Spliceosome malfunction causes neurodevelopmental disorders with overlapping features

Pre-mRNA splicing is a highly coordinated process. While its dysregulation has been linked to neurological deficits, our understanding of the underlying molecular and cellular mechanisms remains limited. We implicated pathogenic variants in U2AF2 and PRPF19, encoding spliceosome subunits in neurodevelopmental disorders (NDDs), by identifying 46 unrelated individuals with 23 de novo U2AF2 missense variants (including 7 recurrent variants in 30 individuals) and 6 individuals with de novo PRPF19 variants. Eight U2AF2 variants dysregulated splicing of a model substrate. Neuritogenesis was reduced in human neurons differentiated from human pluripotent stem cells carrying two U2AF2 hyper-recurrent variants. Neural loss of function (LoF) of the Drosophila orthologs U2af50 and Prp19 led to lethality, abnormal mushroom body (MB) patterning, and social deficits, which were differentially rescued by wild-type and mutant U2AF2 or PRPF19. Transcriptome profiling revealed splicing substrates or effectors (including Rbfox1, a third splicing factor), which rescued MB defects in U2af50deficient flies. Upon reanalysis of negative clinical exomes followed by data sharing, we further identified 6 patients with NDD who carried RBFOX1 missense variants which, by in vitro testing, showed LoF. Our study implicates 3 splicing factors as NDD-causative genes and establishes a genetic network with hierarchy underlying human brain development and function

Genetic and phenotypic spectrum in the NONO-associated syndromic disorder

The non-POU domain-containing octamer-binding (NONO) protein is involved in multiple steps of gene regulation such as RNA metabolism and DNA repair. Hemizygous pathogenic variants in the NONO gene were confirmed to cause a rare X-linked syndromic disorder. Through our in-house diagnostics and subsequent matchmaking, we identified six unrelated male individuals with pathogenic or likely pathogenic NONO variants. For a detailed comparison, we reviewed all published characterizations of the NONO-associated disorder. The combined cohort consists of 16 live-born males showing developmental delay, corpus callosum anomalies, non-compaction cardiomyopathy and relative macrocephaly as leading symptoms. Seven prenatal literature cases were characterized by cardiac malformations. In this study, we extend the phenotypic spectrum through two more cases with epilepsy as well as two more cases with hematologic anomalies. By RNA expression analysis and structural modeling of a new in-frame splice deletion, we reinforce loss-of-function as the pathomechanism for the NONO-associated syndromic disorder

Spectrum of novel mutations found in Waardenburg syndrome types 1 and 2: implications for molecular genetic diagnostics

Objectives: Till date, mutations in the genes PAX3 and MITF have been described in Waardenburg syndrome (WS), which is clinically characterised by congenital hearing loss and pigmentation anomalies. Our study intended to determine the frequency of mutations and deletions in these genes, to assess the clinical phenotype in detail and to identify rational priorities for molecular genetic diagnostics procedures. Design: Prospective analysis. Patients: 19 Caucasian patients with typical features of WS underwent stepwise investigation of PAX3 and MITF. When point mutations and small insertions/deletions were excluded by direct sequencing, copy number analysis by multiplex ligation-dependent probe amplification was performed to detect larger deletions and duplications. Clinical data and photographs were collected to facilitate genotype-phenotype analyses. Setting: All analyses were performed in a large German laboratory specialised in genetic diagnostics. Results: 15 novel and 4 previously published heterozygous mutations in PAX3 and MITF were identified. Of these, six were large deletions or duplications that were only detectable by copy number analysis. All patients with PAX3 mutations had typical phenotype of WS with dystopia canthorum (WS1), whereas patients with MITF gene mutations presented without dystopia canthorum (WS2). In addition, one patient with bilateral hearing loss and blue eyes with iris stroma dysplasia had a de novo missense mutation (p. Arg217Ile) in MITF. MITF 3-bp deletions at amino acid position 217 have previously been described in patients with Tietz syndrome (TS), a clinical entity with hearing loss and generalised hypopigmentation. Conclusions: On the basis of these findings, we conclude that sequencing and copy number analysis of both PAX3 and MITF have to be recommended in the routine molecular diagnostic setting for patients, WS1 and WS2. Furthermore, our genotype-phenotype analyses indicate that WS2 and TS correspond to a clinical spectrum that is influenced by MITF mutation type and position

KBG syndrome mimicking genetic generalized epilepsy

•Several conditions may mimic Genetic Generalized Epilepsy GGE. •GGE is less frequently misdiagnosed compared to other subtypes of epilepsy. •KBG syndrome is a rare autosomal dominant condition. •KBG syndrome may mimic GGE.</p

Germline mosaicism in a family with MBD5 haploinsufficiency

Haploinsufficiency of the methyl-CpG-binding domain protein 5 (MBD5) gene causes a neurodevelopmental disorder that includes intellectual disability, developmental delay, speech impairment, seizures, sleep disturbances, and behavioral difficulties. Microdeletion of 2q23.1 is the most common cause of haploinsufficiency, although MBD5 haploinsufficiency may also cause this genetic disorder. We report a family harboring a heterozygous loss-of-function variant in MBD5 (NM_018328.5:c.728delC; p.Pro243Hisfs*26), which includes three affected siblings with varying phenotypic features. Both parents were phenotypically normal but deep coverage sequencing of the parents showed germline mosaicism in the mother. </p

Development of a genomics module within an epilepsy-specific electronic health record: Toward genomic medicine in epilepsy care

Objectives: Both clinical genomics and e-Health technology are changing the way medicine is being practiced. Although the basic clinical methodology of good medical care will remain unchanged, the combined power of genomics and electronic health records has the capability of enhancing, and in some cases transforming, the practice of medicine. This is particularly true in the care of patients with complex long-term medical conditions such as chronic refractory epilepsy, especially in those with related complex comorbidities including intellectual disability and psychiatric disease.Methods: Herein we outline the development and integration of an epilepsy genomics module into a preexisting epilepsy electronic patient record (EPR) system.Results: We describe how this EPR infrastructure is used to facilitate discussion at multidisciplinary clinical meetings around molecular diagnosis and resulting changes in management.Significance: This work illustrates the role of eHealth technology in embedding genomics into the clinical pathway.</div