Towards controlled terminology for reporting germline cancer susceptibility variants: an ENIGMA report.

The vocabulary currently used to describe genetic variants and their consequences reflects many years of studying and discovering monogenic disease with high penetrance. With the recent rapid expansion of genetic testing brought about by wide availability of high-throughput massively parallel sequencing platforms, accurate variant interpretation has become a major issue. The vocabulary used to describe single genetic variants in silico, in vitro, in vivo and as a contributor to human disease uses terms in common, but the meaning is not necessarily shared across all these contexts. In the setting of cancer genetic tests, the added dimension of using data from genetic sequencing of tumour DNA to direct treatment is an additional source of confusion to those who are not experienced in cancer genetics. The language used to describe variants identified in cancer susceptibility genetic testing typically still reflects an outdated paradigm of Mendelian inheritance with dichotomous outcomes. Cancer is a common disease with complex genetic architecture; an improved lexicon is required to better communicate among scientists, clinicians and patients, the risks and implications of genetic variants detected. This review arises from a recognition of, and discussion about, inconsistencies in vocabulary usage by members of the ENIGMA international multidisciplinary consortium focused on variant classification in breast-ovarian cancer susceptibility genes. It sets out the vocabulary commonly used in genetic variant interpretation and reporting, and suggests a framework for a common vocabulary that may facilitate understanding and clarity in clinical reporting of germline genetic tests for cancer susceptibility

HACE1 deficiency causes an autosomal recessive neurodevelopmental syndrome

Background: The genetic etiology of neurodevelopmental defects is extremely diverse, and the lack of distinctive phenotypic features means that genetic criteria are often required for accurate diagnostic classification. We aimed to identify the causative genetic lesions in two families in which eight affected individuals displayed variable learning disability, spasticity and abnormal gait. Methods: Autosomal recessive inheritance was suggested by consanguinity in one family and by sibling recurrences with normal parents in the second. Autozygosity mapping and exome sequencing, respectively, were used to identify the causative gene. Results: In both families, biallelic loss-of-function mutations in HACE1 were identified. HACE1 is an E3 ubiquitin ligase that regulates the activity of cellular GTPases, including Rac1 and members of the Rab family. In the consanguineous family, a homozygous mutation p.R219* predicted a truncated protein entirely lacking its catalytic domain. In the other family, compound heterozygosity for nonsense mutation p.R748* and a 20-nt insertion interrupting the catalytic HECT domain was present; Western analysis of patient cells revealed an absence of detectable HACE1 protein. Conclusion: HACE1 mutations underlie a new autosomal recessive neurodevelopmental disorder. Previous studies have implicated HACE1 as a tumour suppressor gene; however, since cancer predisposition was not observed either in homozygous or heterozygous mutation carriers, this concept may require re-evaluation

A common allele in RPGRIP1L is a modifier of retinal degeneration in ciliopathies

Despite rapid advances in the identification of genes involved in disease, the predictive power of the genotype remains limited, in part owing to poorly understood effects of second-site modifiers. Here we demonstrate that a polymorphic coding variant of RPGRIP1L (retinitis pigmentosa GTPase regulator-interacting protein-1 like), a ciliary gene mutated in Meckel-Gruber (MKS) and Joubert (JBTS) syndromes, is associated with the development of retinal degeneration in individuals with ciliopathies caused by mutations in other genes. As part of our resequencing efforts of the ciliary proteome, we identified several putative loss-of-function RPGRIP1L mutations, including one common variant, A229T. Multiple genetic lines of evidence showed this allele to be associated with photoreceptor loss in ciliopathies. Moreover, we show that RPGRIP1L interacts biochemically with RPGR, loss of which causes retinal degeneration, and that the Thr229-encoded protein significantly compromises this interaction. Our data represent an example of modification of a discrete phenotype of syndromic disease and highlight the importance of a multifaceted approach for the discovery of modifier alleles of intermediate frequency and effect.This work was supported by grants R01EY007961 from the National Eye Institute (H.K. and A.S.), R01HD04260 from the National Institute of Child Health and Development (N.K.), R01DK072301, R01DK075972 (N.K.), R01DK068306, R01DK064614, R01DK069274 (F.H.), NRSA fellowship F32 DK079541 (E.E.D.) from the National Institute of Diabetes, Digestive and Kidney disorders, Intramural program of NEI (A.S.), the Macular Vision Research Foundation (N.K.), the Foundation for Fighting Blindness (H.K., S.S.B., A.S. and N.K.), the Foundation for Fighting Blindness Canada (R.K.K.), Le Fonds de la recherche en sante du Québec (FRSQ) (R.K.K.), Research to Prevent Blindness (A.S.), Harold Falls Collegiate Professorship (A.S.), the Midwest Eye Banks and Transplantation Center (H.K.), the Searle Scholars Program (M.A.B.), the Deutsche Forschungsgemeinschaft (DFG grant BE 3910/4-1; C.B.) the UK Medical Research Council (grant number G0700073; C.A.J.), NIHR Biomedical Research Centre for Ophthalmology (S.S.B.) and EU-GENORET Grant LSHG-CT-2005-512036 (S.S.B.). F.H. is an investigator of the Howard Hughes Medical Institute (HHMI) and a Doris Duke Distinguished Clinical Scientist (DDCF)

Loss of the Metalloprotease ADAM9 Leads to Cone-Rod Dystrophy in Humans and Retinal Degeneration in Mice

Cone-rod dystrophy (CRD) is an inherited progressive retinal dystrophy affecting the function of cone and rod photoreceptors. By autozygosity mapping, we identified null mutations in the ADAM metallopeptidase domain 9 (ADAM9) gene in four consanguineous families with recessively inherited early-onset CRD. We also found reduced photoreceptor responses in Adam9 knockout mice, previously reported to be asymptomatic. In 12-month-old knockout mice, photoreceptors appear normal, but the apical processes of the retinal pigment epithelium (RPE) cells are disorganized and contact between photoreceptor outer segments (POSs) and the RPE apical surface is compromised. In 20-month-old mice, there is clear evidence of progressive retinal degeneration with disorganized POS and thinning of the outer nuclear layer (ONL) in addition to the anomaly at the POS-RPE junction. RPE basal deposits and macrophages were also apparent in older mice. These findings therefore not only identify ADAM9 as a CRD gene but also identify a form of pathology wherein retinal disease first manifests at the POS-RPE junction

Mutation screening of retinal dystrophy patients by targeted capture from tagged pooled DNAs and next generation sequencing.

Purpose: Retinal dystrophies are genetically heterogeneous, resulting from mutations in over 200 genes. Prior to the development of massively parallel sequencing, comprehensive genetic screening was unobtainable for most patients. Identifying the causative genetic mutation facilitates genetic counselling, carrier testing and prenatal/pre-implantation diagnosis, and often leads to a clearer prognosis. In addition, in a proportion of cases, when the mutation is known treatment can be optimised and patients are eligible for enrolment into clinical trials for gene-specific therapies. Methods: Patient genomic DNA was sheared, tagged and pooled in batches of four samples, prior to targeted capture and next generation sequencing. The enrichment reagent was designed against genes listed on the RetNet database (July 2010). Sequence data were aligned to the human genome and variants were filtered to identify potential pathogenic mutations. These were confirmed by Sanger sequencing. Results: Molecular analysis of 20 DNAs from retinal dystrophy patients identified likely pathogenic mutations in 12 cases, many of them known and/or confirmed by segregation. These included previously described mutations in ABCA4 (c.6088C>T,p.R2030*; c.5882G>A,p.G1961E), BBS2 (c.1895G>C,p.R632P), GUCY2D (c.2512C>T,p.R838C), PROM1 (c.1117C>T,p.R373C), RDH12 (c.601T>C,p.C201R; c.506G>A,p.R169Q), RPGRIP1 (c.3565C>T,p.R1189*) and SPATA7 (c.253C>T,p.R85*) and new mutations in ABCA4 (c.3328+1G>C), CRB1 (c.2832_2842+23del), RP2 (c.884-1G>T) and USH2A (c.12874A>G,p.N4292D). Conclusions: Tagging and pooling DNA prior to targeted capture of known retinal dystrophy genes identified mutations in 60% of cases. This relatively high success rate may reflect enrichment for consanguineous cases in the local Yorkshire population, and the use of multiplex families. Nevertheless this is a promising high throughput approach to retinal dystrophy diagnostics

DNA Polymerase Epsilon Deficiency Causes IMAGe Syndrome with Variable Immunodeficiency.

During genome replication, polymerase epsilon (Pol ε) acts as the major leading-strand DNA polymerase. Here we report the identification of biallelic mutations in POLE, encoding the Pol ε catalytic subunit POLE1, in 15 individuals from 12 families. Phenotypically, these individuals had clinical features closely resembling IMAGe syndrome (intrauterine growth restriction [IUGR], metaphyseal dysplasia, adrenal hypoplasia congenita, and genitourinary anomalies in males), a disorder previously associated with gain-of-function mutations in CDKN1C. POLE1-deficient individuals also exhibited distinctive facial features and variable immune dysfunction with evidence of lymphocyte deficiency. All subjects shared the same intronic variant (c.1686+32C>G) as part of a common haplotype, in combination with different loss-of-function variants in trans. The intronic variant alters splicing, and together the biallelic mutations lead to cellular deficiency of Pol ε and delayed S-phase progression. In summary, we establish POLE as a second gene in which mutations cause IMAGe syndrome. These findings add to a growing list of disorders due to mutations in DNA replication genes that manifest growth restriction alongside adrenal dysfunction and/or immunodeficiency, consolidating these as replisome phenotypes and highlighting a need for future studies to understand the tissue-specific development roles of the encoded proteins

Mutations in the pH-Sensing G-protein-Coupled Receptor GPR68 Cause Amelogenesis Imperfecta

Amelogenesis is the process of dental enamel formation, leading to the deposition of the hardest tissue in the human body. This process requires the intricate regulation of ion transport and controlled changes to the developing enamel matrix pH. The means by which the enamel organ regulates pH during amelogenesis is largely unknown. We identified rare homozygous variants in GPR68 in three families with Amelogenesis Imperfecta, a genetically and phenotypically heterogeneous group of inherited conditions associated with abnormal enamel formation. Each of these homozygous variants (a large in-frame deletion, a frameshift deletion and a missense) were predicted to result in loss of function. GPR68 encodes a proton sensing G-protein-coupled receptor with sensitivity in the pH range that occurs in the developing enamel matrix during amelogenesis. Immunohistochemistry of rat mandibles confirmed localisation of GPR68 in the enamel organ at all stages of amelogenesis. Our data identify a role for GPR68 as a proton sensor that is required for proper enamel formation

A legal analysis of Australian criminal cases involving defendants with autism spectrum disorder charged with online sexual offending

This paper examines how the symptomology of the small number of individuals with autism spectrum disorder (ASD) charged with online sexual offenses in Australia is established during legal arguments and conceived by the judiciary to impact legal liability and offending behavior. This study aims to provide empirical support for the proposition that judicial discourses regarding the connection between ASD and online sexual offending, including conduct related to child exploitation material (CEM), have little bearing on overall questions of criminal liability or the use of alternative penal dispositions. It does so by exploring a sample of nine recent Australian criminal cases, involving ten rulings, that examine how evidence of ASD is raised in legal arguments in ways that suggest a diagnosed condition may have contributed significantly to the alleged wrongdoing. We conclude by suggesting current Australian judicial practice requires more sensitivity to the impact of clinical factors associated with ASD in shaping alternative supervisory and non-custodial dispositions for individuals convicted of online sexual offenses. Previous article in issu

De novo CCND2 mutations leading to stabilization of cyclin D2 cause megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome

Activating mutations in genes encoding phosphatidylinositol 3-kinase (PI3K)-AKT pathway components cause megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome (MPPH, OMIM 603387). Here we report that individuals with MPPH lacking upstream PI3K-AKT pathway mutations carry de novo mutations in CCND2 (encoding cyclin D2) that are clustered around a residue that can be phosphorylated by glycogen synthase kinase 3β (GSK-3β). Mutant CCND2 was resistant to proteasomal degradation in vitro compared to wild-type CCND2. The PI3K-AKT pathway modulates GSK-3β activity, and cells from individuals with PIK3CA, PIK3R2 or AKT3 mutations showed similar CCND2 accumulation. CCND2 was expressed at higher levels in brains of mouse embryos expressing activated AKT3. In utero electroporation of mutant CCND2 into embryonic mouse brains produced more proliferating transfected progenitors and a smaller fraction of progenitors exiting the cell cycle compared to cells electroporated with wild-type CCND2. These observations suggest that cyclin D2 stabilization, caused by CCND2 mutation or PI3K-AKT activation, is a unifying mechanism in PI3K-AKT–related megalencephaly syndromes