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1.
Am J Med Genet A ; 2020 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-33037779

RESUMO

Inherited optic neuropathies (IONs) are neurodegenerative disorders characterized by optic atrophy with or without extraocular manifestations. Optic atrophy-10 (OPA10) is an autosomal recessive ION recently reported to be caused by mutations in RTN4IP1, which encodes reticulon 4 interacting protein 1 (RTN4IP1), a mitochondrial ubiquinol oxydo-reductase. Here we report novel compound heterozygous mutations in RTN4IP1 in a male proband with developmental delay, epilepsy, optic atrophy, ataxia, and choreoathetosis. Workup was notable for transiently elevated lactate and lactate-to-pyruvate ratio, brain magnetic resonance imaging with optic atrophy and T2 signal abnormalities, and a nondiagnostic initial genetic workup, including chromosomal microarray and mitochondrial panel testing. Exome sequencing identified a paternally inherited missense variant (c.263T>G, p.Val88Gly) predicted to be deleterious and a maternally inherited deletion encompassing RTN4IP1. To our knowledge, this is the first report of a non-single nucleotide pathogenic variant associated with OPA10. This case highlights the expanding phenotypic spectrum of OPA10, the association between "syndromic" cases and severe RTN4IP1 mutations, and the importance of nonbiased genetic testing, such as ES, to analyze multiple genes and variants types, in patients suspected of having genetic disease.

2.
Am J Pathol ; 2020 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-32919980

RESUMO

Centronuclear myopathies (CNMs) are a subtype of congenital myopathies characterized by skeletal muscle weakness and an increase in the number of central myonuclei. SPEG (striated preferentially expressed protein kinase) has been identified as the sixth gene associated with CNM, and it has been shown that striated muscle-specific Speg knockout (KO) mice have defective triad formation, abnormal excitation-contraction coupling and calcium mishandling. The impact of SPEG deficiency on the survival and function of myogenic cells remains to be deciphered. In this study, the authors examined the overall population, proliferation, and differentiation of myogenic cells obtained from striated-muscle-specific Speg-KO mice and compared them with wild-type (WT) controls. SPEG-deficient skeletal muscles contained fewer myogenic cells, which on further study demonstrated reduced proliferation and delayed differentiation compared with those from WT. Regenerative response to skeletal muscle injury in Speg-KO was compared with that of WT, leading to the identification of similar abnormalities including fewer satellite cells, fewer dividing cells, and an increase in apoptotic cells in KO mice. Overall, these results reveal specific abnormalities in myogenic cell number and behavior associated with SPEG deficiency. Similar satellite cell defects have been reported in mouse models of MTM1- and DNM2-associated CNM, suggestive of shared underlying pathways.

3.
Artigo em Inglês | MEDLINE | ID: mdl-32826208

RESUMO

Congenital anomalies are common, with 2%-3% of infants estimated to have at least one major congenital malformation and countless others with minor malformations of lesser cosmetic or medical importance. As congenital malformations are major drivers of morbidity and mortality, representing the leading cause of infant mortality in the United States, there is substantial interest in understanding the underlying etiologies-particularly if modifiable causes may be identified or pre- or postnatal treatments can be offered. Recent research has begun to reveal the spectrum of monogenic disorders that commonly result in birth defects, and newer approaches have revealed non-Mendelian genetic contributions including gene-environment interactions. Our experience suggests that increased efforts to sequence and analyze cases of perinatal death, as well as continued global collaboration, will be essential in understanding the genomic landscape of structural anomalies.

4.
Int J Pediatr Otorhinolaryngol ; 138: 110283, 2020 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-32771712

RESUMO

INTRODUCTION: Laryngeal clefts are rare congenital anomalies characterized by failed fusion of the posterior cricoid lamina or incomplete development of the tracheoesophageal septum. While most cases are sporadic, laryngeal cleft may be associated with other congenital anomalies or syndromes. Though not frequently reported, familial occurrence of laryngeal cleft has been noted in our clinical experience. The goal of this research is to describe the existing literature and our own experience surrounding familial occurrence of laryngeal cleft that may help elucidate its underlying genetic basis. METHODS: Comprehensive literature search was conducted and retrospective chart review was performed on 8 sets of siblings diagnosed at our institution. Data assessed included demographics, type of cleft, and genetic findings. RESULTS: Laryngeal cleft appears to be mostly sporadic. We evaluated data at our institution over a 10-year period and identified 19 patients from 8 families demonstrating familial occurrence of laryngeal cleft. Six (75%) families had two affected siblings, one family (12.5%) had three affected siblings, and one family (12.5%) had four affected siblings. There was no evidence of sex predilection, with half the patients being male (10/19, 52.6%). Fourteen patients (73.7%) had Type 1 clefts and five (26.3%) had Type 2 clefts. Genetic findings were available for review in five patients from three families. CONCLUSION: Beyond a few known syndromes, laryngeal cleft has largely been thought to be sporadic. However, findings from the existing literature and our own experience with familial laryngeal cleft in eight families suggest additional genetic factors are yet to be elucidated.

6.
Mol Psychiatry ; 2020 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-32346159

RESUMO

Defects in histone methyltransferases (HMTs) are major contributing factors in neurodevelopmental disorders (NDDs). Heterozygous variants of SETD1A involved in histone H3 lysine 4 (H3K4) methylation were previously identified in individuals with schizophrenia. Here, we define the clinical features of the Mendelian syndrome associated with haploinsufficiency of SETD1A by investigating 15 predominantly pediatric individuals who all have de novo SETD1A variants. These individuals present with a core set of symptoms comprising global developmental delay and/or intellectual disability, subtle facial dysmorphisms, behavioral and psychiatric problems. We examined cellular phenotypes in three patient-derived lymphoblastoid cell lines with three variants: p.Gly535Alafs*12, c.4582-2_4582delAG, and p.Tyr1499Asp. These patient cell lines displayed DNA damage repair defects that were comparable to previously observed RNAi-mediated depletion of SETD1A. This suggested that these variants, including the p.Tyr1499Asp in the catalytic SET domain, behave as loss-of-function (LoF) alleles. Previous studies demonstrated a role for SETD1A in cell cycle control and differentiation. However, individuals with SETD1A variants do not show major structural brain defects or severe microcephaly, suggesting that defective proliferation and differentiation of neural progenitors is unlikely the single underlying cause of the disorder. We show here that the Drosophila melanogaster SETD1A orthologue is required in postmitotic neurons of the fly brain for normal memory, suggesting a role in post development neuronal function. Together, this study defines a neurodevelopmental disorder caused by dominant de novo LoF variants in SETD1A and further supports a role for H3K4 methyltransferases in the regulation of neuronal processes underlying normal cognitive functioning.

8.
Am J Hum Genet ; 106(4): 570-583, 2020 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-32197074

RESUMO

EIF2AK1 and EIF2AK2 encode members of the eukaryotic translation initiation factor 2 alpha kinase (EIF2AK) family that inhibits protein synthesis in response to physiologic stress conditions. EIF2AK2 is also involved in innate immune response and the regulation of signal transduction, apoptosis, cell proliferation, and differentiation. Despite these findings, human disorders associated with deleterious variants in EIF2AK1 and EIF2AK2 have not been reported. Here, we describe the identification of nine unrelated individuals with heterozygous de novo missense variants in EIF2AK1 (1/9) or EIF2AK2 (8/9). Features seen in these nine individuals include white matter alterations (9/9), developmental delay (9/9), impaired language (9/9), cognitive impairment (8/9), ataxia (6/9), dysarthria in probands with verbal ability (6/9), hypotonia (7/9), hypertonia (6/9), and involuntary movements (3/9). Individuals with EIF2AK2 variants also exhibit neurological regression in the setting of febrile illness or infection. We use mammalian cell lines and proband-derived fibroblasts to further confirm the pathogenicity of variants in these genes and found reduced kinase activity. EIF2AKs phosphorylate eukaryotic translation initiation factor 2 subunit 1 (EIF2S1, also known as EIF2α), which then inhibits EIF2B activity. Deleterious variants in genes encoding EIF2B proteins cause childhood ataxia with central nervous system hypomyelination/vanishing white matter (CACH/VWM), a leukodystrophy characterized by neurologic regression in the setting of febrile illness and other stressors. Our findings indicate that EIF2AK2 missense variants cause a neurodevelopmental syndrome that may share phenotypic and pathogenic mechanisms with CACH/VWM.


Assuntos
Deficiências do Desenvolvimento/genética , Variação Genética/genética , Leucoencefalopatias/genética , Malformações do Sistema Nervoso/genética , eIF-2 Quinase/genética , Adolescente , Ataxia/genética , Criança , Pré-Escolar , Feminino , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/genética , Humanos , Lactente , Masculino , Substância Branca/patologia
9.
Hum Mol Genet ; 29(12): 1996-2003, 2020 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-32160286

RESUMO

Cofilin-2 is an actin-binding protein that is predominantly expressed in skeletal and cardiac muscles and belongs to the AC group of proteins, which includes cofilin-1 and destrin. In humans, cofilin-2 (CFL2) mutations have been associated with congenital myopathies that include nemaline and myofibrillar myopathy. To understand the pathogenicity of the human CFL2 mutation, p.A35T, that first linked cofilin-2 with the human disease, we created a knock-in mouse model. The Cfl2A35T/A35T (KI) mice were indistinguishable from their wild-type littermates at birth, but they rapidly worsened and died by postnatal day 9. The phenotypic, histopathologic and molecular findings mimicked the constitutive Cfl2-knockout (KO) mice described previously, including sarcomeric disruption and actin accumulations in skeletal muscles and negligible amounts of cofilin-2 protein. In addition, KI mice demonstrated a marked reduction in Cfl2 mRNA levels in various tissues including skeletal muscles. Further investigation revealed evidence of alternative splicing with the presence of two alternate transcripts of smaller size. These alternate transcripts were expressed at very low levels in the wild-type mice and were significantly upregulated in the mutant mice, indicating that pre-translational splicing defects may be a critical component of the disease mechanism associated with the mutation. Evidence of reduced expression of the full-length CFL2 transcript was also observed in the muscle biopsy sample of the patient with p.A35T mutation.

10.
Artigo em Inglês | MEDLINE | ID: mdl-32022391

RESUMO

3-Hydroxyisobutyryl-CoA dehydrogenase (HIBCH) deficiency is a rare error in valine catabolism associated with a Leigh syndrome-like phenotype, mitochondrial dysfunction, and increased C4-OH. We report the most severe case to date in a full-term female who presented with poor feeding and nystagmus on day of life (DOL) 1. Although initial neuroimaging findings were concerning for metabolic disease, further metabolic testing was nondiagnostic and she was discharged on DOL 18. She was readmitted on DOL 22 after severe apneic episodes requiring intubation, with EEG demonstrating multifocal seizures and MRI/MRS demonstrating worsening findings. Care was withdrawn DOL 27 and she expired. Rapid whole exome sequencing (WES) demonstrated compound heterozygous variants in HIBCH with a paternal pathogenic variant (c.852delA, p.L284FfsX10) and a maternal likely pathogenic variant (c.488G>T, p.C163F). Fibroblast enzymatic testing demonstrated marked reduction in HIBCH levels. This case demonstrates the importance of rapid WES and follow-up functional testing in establishing a diagnosis when metabolic disease is suspected but lacks an expected biochemical signature.

11.
J Perinatol ; 40(7): 997-1006, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32094481

RESUMO

Many genetic disorders are detectable in the prenatal period, and the capacity to identify them has increased remarkably as molecular genetic testing techniques continue to improve and become incorporated into clinical practice. The indications for prenatal genetic testing vary widely, including follow-up of an anomaly found by routine ultrasound or maternal aneuploidy screening, a family history of genetic disease, advanced maternal or paternal age, or evaluation of a low-risk pregnancy due to parental concern. The interpretation of genetic variants identified in the prenatal period poses unique challenges due to the lack of ability for deep phenotyping as well as the option to make critical decisions regarding pregnancy continuation and perinatal management. In this review, we address the various modalities currently available and commonly used for genetic testing, including preimplantation genetic testing of embryos, cell-free DNA testing, and diagnostic procedures such as chorionic villous sampling, amniocentesis, or percutaneous umbilical blood sampling, from which samples may be sent for a wide variety of genetic tests. We discuss the difference between these modalities for the genetic diagnosis of a fetus, their strengths and weaknesses, and strategies for their optimal use in order to direct perinatal care.

12.
J Clin Invest ; 130(3): 1431-1445, 2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-31794431

RESUMO

Epigenetic integrity is critical for many eukaryotic cellular processes. An important question is how different epigenetic regulators control development and influence disease. Lysine acetyltransferase 8 (KAT8) is critical for acetylation of histone H4 at lysine 16 (H4K16), an evolutionarily conserved epigenetic mark. It is unclear what roles KAT8 plays in cerebral development and human disease. Here, we report that cerebrum-specific knockout mice displayed cerebral hypoplasia in the neocortex and hippocampus, along with improper neural stem and progenitor cell (NSPC) development. Mutant cerebrocortical neuroepithelia exhibited faulty proliferation, aberrant neurogenesis, massive apoptosis, and scant H4K16 propionylation. Mutant NSPCs formed poor neurospheres, and pharmacological KAT8 inhibition abolished neurosphere formation. Moreover, we describe KAT8 variants in 9 patients with intellectual disability, seizures, autism, dysmorphisms, and other anomalies. The variants altered chromobarrel and catalytic domains of KAT8, thereby impairing nucleosomal H4K16 acetylation. Valproate was effective for treating epilepsy in at least 2 of the individuals. This study uncovers a critical role of KAT8 in cerebral and NSPC development, identifies 9 individuals with KAT8 variants, and links deficient H4K16 acylation directly to intellectual disability, epilepsy, and other developmental anomalies.

13.
Genet Med ; 22(4): 736-744, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31780822

RESUMO

PURPOSE: To investigate the impact of rapid-turnaround exome sequencing in critically ill neonates using phenotype-based subject selection criteria. METHODS: Intensive care unit babies aged <6 months with hypotonia, seizures, a complex metabolic phenotype, and/or multiple congenital malformations were prospectively enrolled for rapid (<7 day) trio-based exome sequencing. Genomic variants relevant to the presenting phenotype were returned to the medical team. RESULTS: A genetic diagnosis was attained in 29 of 50 (58%) sequenced cases. Twenty-seven (54%) patients received a molecular diagnosis involving known disease genes; two additional cases (4%) were solved with pathogenic variants found in novel disease genes. In 24 of the solved cases, diagnosis had impact on patient management and/or family members. Management changes included shift to palliative care, medication changes, involvement of additional specialties, and the consideration of new experimental therapies. CONCLUSION: Phenotype-based patient selection is effective at identifying critically ill neonates with a high likelihood of receiving a molecular diagnosis via rapid-turnaround exome sequencing, leading to faster and more accurate diagnoses, reducing unnecessary testing and procedures, and informing medical care.

14.
Artigo em Inglês | MEDLINE | ID: mdl-31633297

RESUMO

Hennekam lymphangiectasia-lymphedema syndrome is an autosomal recessive disorder characterized by congenital lymphedema, intestinal lymphangiectasia, facial dysmorphism, and variable intellectual disability. Known disease genes include CCBE1, FAT4, and ADAMTS3. In a patient with clinically diagnosed Hennekam syndrome but without mutations or copy-number changes in the three known disease genes, we identified a homozygous single-exon deletion affecting FBXL7. Specifically, exon 3, which encodes the F-box domain and several leucine-rich repeats of FBXL7, is eliminated. Our analyses of databases representing >100,000 control individuals failed to identify biallelic loss-of-function variants in FBXL7. Published studies in Drosophila indicate Fbxl7 interacts with Fat, of which human FAT4 is an ortholog, and mutation of either gene yields similar morphological consequences. These data suggest that FBXL7 may be the fourth gene for Hennekam syndrome, acting via a shared pathway with FAT4.

15.
NPJ Genom Med ; 4: 32, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31839987

RESUMO

The National Institutes of Health (NIH) funded the Newborn Sequencing In Genomic medicine and public HealTh (NSIGHT) Consortium to investigate the implications, challenges, and opportunities associated with the possible use of genomic sequence information in the newborn period. Following announcement of the NSIGHT awardees in 2013, the Food and Drug Administration (FDA) contacted investigators and requested that pre-submissions to investigational device exemptions (IDE) be submitted for the use of genomic sequencing under Title 21 of the Code of Federal Regulations (21 CFR) part 812. IDE regulation permits clinical investigation of medical devices that have not been approved by the FDA. To our knowledge, this marked the first time the FDA determined that NIH-funded clinical genomic research projects are subject to IDE regulation. Here, we review the history of and rationale behind FDA oversight of clinical research and the NSIGHT Consortium's experiences in navigating the IDE process. Overall, NSIGHT investigators found that FDA's application of existing IDE regulations and medical device definitions aligned imprecisely with the aims of publicly funded exploratory clinical research protocols. IDE risk assessments by the FDA were similar to, but distinct from, protocol risk assessments conducted by local Institutional Review Boards (IRBs), and had the potential to reflect novel oversight of emerging genomic technologies. However, the pre-IDE and IDE process delayed the start of NSIGHT research studies by an average of 10 months, and significantly limited the scope of investigation in two of the four NIH approved projects. Based on the experience of the NSIGHT Consortium, we conclude that policies and practices governing the development and use of novel genomic technologies in clinical research urgently need clarification in order to mitigate potentially conflicting or redundant oversight by IRBs, NIH, FDA, and state authorities.

16.
N Engl J Med ; 381(17): 1644-1652, 2019 10 24.
Artigo em Inglês | MEDLINE | ID: mdl-31597037

RESUMO

Genome sequencing is often pivotal in the diagnosis of rare diseases, but many of these conditions lack specific treatments. We describe how molecular diagnosis of a rare, fatal neurodegenerative condition led to the rational design, testing, and manufacture of milasen, a splice-modulating antisense oligonucleotide drug tailored to a particular patient. Proof-of-concept experiments in cell lines from the patient served as the basis for launching an "N-of-1" study of milasen within 1 year after first contact with the patient. There were no serious adverse events, and treatment was associated with objective reduction in seizures (determined by electroencephalography and parental reporting). This study offers a possible template for the rapid development of patient-customized treatments. (Funded by Mila's Miracle Foundation and others.).


Assuntos
Proteínas de Membrana Transportadoras/genética , Mutagênese Insercional , Lipofuscinoses Ceroides Neuronais/tratamento farmacológico , Lipofuscinoses Ceroides Neuronais/genética , Oligonucleotídeos Antissenso/uso terapêutico , Medicina de Precisão , Doenças Raras/tratamento farmacológico , Biópsia , Criança , Desenvolvimento Infantil , Descoberta de Drogas , Drogas em Investigação/uso terapêutico , Eletroencefalografia , Feminino , Humanos , Testes Neuropsicológicos , RNA Mensageiro , Convulsões/diagnóstico , Convulsões/tratamento farmacológico , Pele/patologia , Sequenciamento Completo do Genoma
18.
J Perinatol ; 39(12): 1611-1619, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31395954

RESUMO

OBJECTIVE: To determine the proportion of infant deaths occurring in the setting of a confirmed genetic disorder. STUDY DESIGN: A retrospective analysis of the electronic medical records of infants born from 1 January, 2011 to 1 June, 2017, who died prior to 1 year of age. RESULTS: Five hundred and seventy three deceased infants were identified. One hundred and seventeen were confirmed to have a molecular or cytogenetic diagnosis in a clinical diagnostic laboratory and an additional seven were diagnosed by research testing for a total of 124/573 (22%) diagnosed infants. A total of 67/124 (54%) had chromosomal disorders and 58/124 (47%) had single gene disorders (one infant had both). The proportion of diagnoses made by sequencing technologies, such as exome sequencing, increased over the years. CONCLUSIONS: The prevalence of confirmed genetic disorders within our cohort of infant deaths is higher than that previously reported. Increased efforts are needed to further understand the mortality burden of genetic disorders in infancy.

19.
Sci Rep ; 9(1): 10726, 2019 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-31341179

RESUMO

Non-immune hydrops fetalis (NIHF) is a complex condition with a high mortality and morbidity rate. Here we report the etiology and outcome of 1004 fetuses with NIHF, in a large single Maternal and Children's hospital of Southern China, since the year of 2009 to 2016. Among these 1004 fetuses with NIHF, the etiology was identified prenatally in 722 of them (72%). The most common ones were hematologic diseases and chromosomal abnormalities. There were eight spontaneous abortions, 18 intrauterine fetal demise, 672 pregnancy terminations and 87 were lost to follow-up. 219 of the 1004 fetuses were live-born and the overall survival rate was 21.8% at this point. After birth 16 perinatal or early neonatal deaths were encountered and five lost to follow-up. Of the remaining 198 newborns, 153 thrived without apparent morbidity. The most significant factors associated with mortality were prematurity and low birthweight. In conclusion, we described the largest report of underlying causes and outcome of NIHF in Southern China. Etiologies were identified for 72% of 1004 fetuses with NIHF. And two poor prognostic factors for survival are preterm birth at less than 36.5 weeks and birthweight lower than 2575 g respectively.

20.
Am J Hum Genet ; 105(2): 413-424, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31327508

RESUMO

WD40 repeat-containing proteins form a large family of proteins present in all eukaryotes. Here, we identified five pediatric probands with de novo variants in WDR37, which encodes a member of the WD40 repeat protein family. Two probands shared one variant and the others have variants in nearby amino acids outside the WD40 repeats. The probands exhibited shared phenotypes of epilepsy, colobomas, facial dysmorphology reminiscent of CHARGE syndrome, developmental delay and intellectual disability, and cerebellar hypoplasia. The WDR37 protein is highly conserved in vertebrate and invertebrate model organisms and is currently not associated with a human disease. We generated a null allele of the single Drosophila ortholog to gain functional insights and replaced the coding region of the fly gene CG12333/wdr37 with GAL4. These flies are homozygous viable but display severe bang sensitivity, a phenotype associated with seizures in flies. Additionally, the mutant flies fall when climbing the walls of the vials, suggesting a defect in grip strength, and repeat the cycle of climbing and falling. Similar to wall clinging defect, mutant males often lose grip of the female abdomen during copulation. These phenotypes are rescued by using the GAL4 in the CG12333/wdr37 locus to drive the UAS-human reference WDR37 cDNA. The two variants found in three human subjects failed to rescue these phenotypes, suggesting that these alleles severely affect the function of this protein. Taken together, our data suggest that variants in WDR37 underlie a novel syndromic neurological disorder.


Assuntos
Transtornos Dismórficos Corporais/patologia , Cerebelo/anormalidades , Coloboma/patologia , Deficiências do Desenvolvimento/patologia , Epilepsia/patologia , Deficiência Intelectual/patologia , Mutação , Malformações do Sistema Nervoso/patologia , Repetições WD40/genética , Adulto , Sequência de Aminoácidos , Animais , Transtornos Dismórficos Corporais/genética , Cerebelo/patologia , Criança , Coloboma/genética , Deficiências do Desenvolvimento/genética , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Epilepsia/genética , Feminino , Humanos , Lactente , Recém-Nascido , Deficiência Intelectual/genética , Masculino , Proteínas dos Microfilamentos/genética , Proteínas dos Microfilamentos/metabolismo , Malformações do Sistema Nervoso/genética , Fenótipo , Homologia de Sequência , Adulto Jovem
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