To elucidate the common and distinct clinical features of immune-mediated necrotising myopathy (IMNM), also known as necrotising autoimmune myopathy associated with autoantibodies against signal ...recognition particle (SRP) and 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR).
We examined a cohort of 460 patients with idiopathic inflammatory myopathies (IIMs) through a muscle biopsy-oriented registration study in Japan. Study entry was strictly determined by the comprehensive histological assessment to exclude other neuromuscular disorders. Anti-SRP and anti-HMGCR antibodies were detected by RNA immunoprecipitation and ELISA, respectively.
Of 460 patients with IIM, we diagnosed 73 (16%) as having inclusion body myositis (IBM). Of 387 patients with IIMs other than IBM, the frequencies of anti-SRP and anti-HMGCR antibodies were 18% and 12%, respectively. One patient had both autoantibodies. Severe limb muscle weakness, neck weakness, dysphagia, respiratory insufficiency and muscle atrophy were more frequently observed in patients with anti-SRP antibodies than in those with anti-HMGCR antibodies. Serum creatine levels were markedly higher in the patients with autoantibodies than in those without. Histology was characterised by necrosis and regeneration of muscle fibres and was consistent with IMNM except in 1 HMGCR-positive IBM patient. Most patients were initially treated with corticosteroids; however, additional immunosuppressive drugs were required, especially in the patients with anti-SRP antibodies. Rates of unsatisfactory neurological outcome were similar in the 2 autoantibody groups.
Anti-SRP antibodies are associated with severe neurological symptoms, more so than are anti-HMGCR antibodies. Although these autoantibodies are independent serological markers associated with IMNM, patients bearing either share common characteristics.
TET3 at 2p13.1 encodes tet methylcytosine dioxygenase 3, a demethylation enzyme that converts 5-methylcytosine to 5-hydroxymethylcytosine. Beck et al. reported that patients with TET3 abnormalities ...in either an autosomal dominant or recessive inheritance fashion clinically showed global developmental delay, intellectual disability, and dysmorphisms. In this study, exome sequencing identified both mono- and biallelic TET3 variants in two families: a de novo variant NM_001287491.1:c.3028 A > G:p.(Asn1010Asp), and compound heterozygous variants NM_001287491.1:c.2077 C > T;2896 T > G,p.Gln693*;Cys966Gly. Despite the different inheritance modes, the affected individuals showed similar phenotypic features. Including these three patients, only 14 affected individuals have been reported to date. The accumulation of data regarding individuals with TET3-related disorder is necessary to describe their clinical spectrum.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract
Bipolar disorder is a severe mental illness characterized by recurrent manic and depressive episodes. To better understand its genetic architecture, we analyze ultra-rare de novo mutations ...in 354 trios with bipolar disorder. For germline de novo mutations, we find significant enrichment of loss-of-function mutations in constrained genes (corrected-
P
= 0.0410) and deleterious mutations in presynaptic active zone genes (FDR = 0.0415). An analysis integrating single-cell RNA-sequencing data identifies a subset of excitatory neurons preferentially expressing the genes hit by deleterious mutations, which are also characterized by high expression of developmental disorder genes. In the analysis of postzygotic mutations, we observe significant enrichment of deleterious ones in developmental disorder genes (
P
= 0.00135), including the
SRCAP
gene mutated in two unrelated probands. These data collectively indicate the contributions of both germline and postzygotic mutations to the risk of bipolar disorder, supporting the hypothesis that postzygotic mutations of developmental disorder genes may contribute to bipolar disorder.
Biallelic variants in ZNF142 at 2q35, which encodes zinc-finger protein 142, cause neurodevelopmental disorder with seizures or dystonia. We identified compound heterozygous null variants in ZNF142, ...NM_001105537.4:c.1252C>T;1274-2A>G,p.Arg418*;Glu426*, in Malaysian siblings suffering from global developmental delay with epilepsy and dysmorphism. cDNA analysis showed the marked reduction of ZNF142 transcript level through nonsense-mediated mRNA decay by these novel biallelic variants. The affected siblings present with global developmental delay and epilepsy in common, which were previously described, as well as dysmorphism, which was not recognized. It is important to collect patients with ZNF142 abnormality to define its phenotypic spectrum.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Cardiofaciocutaneous syndrome (CFC) is a rare genetic disorder that presents with cardiac, craniofacial, and cutaneous symptoms, and is often accompanied by neurological abnormalities, including ...neurodevelopmental disorders and epilepsy. Regarding epilepsy in CFC, the onset of seizures commonly occurs in childhood. Since research data has mainly been collected from young patients with relatively short observation period, there is insufficient information regarding adult-onset epilepsy in CFC. Here, we report the long-term clinical course of epilepsy and other complications in a 45-year-old female with genetically confirmed CFC carrying a pathogenic de novo heterozygous variant of MAP2K1 , c.389 A>G (p.Tyr130Cys). The patient presented psychomotor delay from infancy and had severe intellectual disability with autistic features. At the age of 30, she first developed combined generalized and focal epilepsy that was resistant to anti-seizure medication. Her refractory epilepsy was fairly controlled with a combination of three anti-seizure medications, especially lacosamide, which effectively suppressed both generalized and focal seizures. The present case provides detailed information regarding the clinical course and treatment of adult-onset epilepsy, which may be useful for optimal treatment and prognostic prediction of CFC.
TNNI2 at 11p15.5 encodes troponin I2, fast skeletal type, which is a member of the troponin I gene family and a component of the troponin complex. Distal arthrogryposis (DA) is characterized by ...congenital limb contractures without primary neurological or muscular effects. DA is inherited in an autosomal dominant fashion and is clinically and genetically heterogeneous. Exome sequencing identified a causative variant in TNNI2 NM_003282.4:c.532T>C p.(Phe178Leu) in a Japanese girl with typical DA2b. Interestingly, the familial study using Sanger sequencing suggested a mosaic variant in her healthy father. Subsequent targeted amplicon-based deep sequencing detected the TNNI2 variant with variant allele frequencies of 9.4-17.7% in genomic DNA derived from peripheral blood leukocytes, saliva, hair, and nails in the father. We confirmed a disease-causing variant in TNNI2 in the proband inherited from her asymptomatic father with its somatic variant. Our case demonstrates that careful clinical and genetic evaluation is required in DA.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The objective of this study was to evaluate the efficacy of whole exome sequencing (WES) for the genetic diagnosis of cases presenting with fetal structural anomalies detected by ultrasonography. WES ...was performed on 19 cases with prenatal structural anomalies. Genomic DNA was extracted from umbilical cords or umbilical blood obtained shortly after birth. WES data were analyzed on prenatal phenotypes alone, and the data were re-analyzed after information regarding the postnatal phenotype was obtained. Based solely on the fetal phenotype, pathogenic, or likely pathogenic, single nucleotide variants were identified in 5 of 19 (26.3%) cases. Moreover, we detected trisomy 21 in two cases by WES-based copy number variation analysis. The overall diagnostic rate was 36.8% (7/19). They were all compatible with respective fetal structural anomalies. By referring to postnatal phenotype information, another candidate variant was identified by a postnatal clinical feature that was not detected in prenatal screening. As detailed phenotyping is desirable for better diagnostic rates in WES analysis, we should be aware that fetal phenotype is a useful, but sometimes limited source of information for comprehensive genetic analysis. It is important to amass more data of genotype-phenotype correlations, especially to appropriately assess the validity of WES in prenatal settings.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We report monozygotic twin girls with syndromic intellectual disability who underwent exome sequencing but with negative pathogenic variants. To search for variants that are unrecognized by exome ...sequencing, high-fidelity long-read genome sequencing (HiFi LR-GS) was applied. A 12-kb copy-neutral inversion was precisely identified by HiFi LR-GS after trio-based variant filtering. This inversion directly disrupted two genes, CPNE9 and BRPF1, the latter of which attracted our attention because pathogenic BRPF1 variants have been identified in autosomal dominant intellectual developmental disorder with dysmorphic facies and ptosis (IDDDFP), which later turned out to be clinically found in the twins. Trio-based HiFi LR-GS together with haplotype phasing revealed that the 12-kb inversion occurred de novo on the maternally transmitted chromosome. This study clearly indicates that submicroscopic copy-neutral inversions are important but often uncharacterized culprits in monogenic disorders and that long-read sequencing is highly advantageous for detecting such inversions involved in genetic diseases.
•HiFi LR-WGS resolved undiagnosed cases of syndromic intellectual disability.•HiFi LR-WGS enabled haplotype-resolved structural variation analysis.•Pathogenic inversions can now be accessed using an “unbiased-genomic” strategy.•Inversions should be explored further to improve diagnostic yield.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
PDF
