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1.
BMC Neurol ; 19(1): 246, 2019 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-31640633

RESUMO

BACKGROUND: To describe a patient with sleep alleviated episodic ataxia type 2 with a novel CACNA1A pathogenic variant and provide a possible link to sleep responsive migraine. CASE PRESENTATION: A 26-year-old woman with recurrent attacks of dizziness, nausea, vomiting, ataxia and dysarthria presented for a possible diagnosis of vestibular migraine. Unique to her attacks was if she could fall asleep for as little as 15 min the spells would subside. If however she remained awake the attacks would continue unabated. A presumed diagnosis of episodic ataxia type 2 was made and she became attack free on acetazolamide without recurrence. Genetic testing demonstrated a novel pathogenic variant in CACNA1A on chromosome 19. This pathogenic variant has not been previously reported in the literature and is suggested to truncate the CACNA1A polypeptide by introducing a premature stop codon. CONCLUSION: A case of episodic ataxia type 2 with a novel pathogenic variant in CACNA1A is described. Interestingly, the patient's symptoms would completely alleviate with sleep which suggests a sleep modulated channelopathy. The mechanisms by which sleep could potentially alter this pathogenic variant are hypothesized. A potential link to sleep alleviated migraine is suggested. Further study of this novel pathogenic variant may help us understand not only how sleep can modulate episodic ataxia type 2, but also migraine.

3.
Am J Med Genet A ; 179(9): 1764-1777, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31240838

RESUMO

Diffuse idiopathic skeletal hyperostosis (DISH) is a disorder principally characterized by calcification and ossification of spinal ligaments and entheses. Fibrodysplasia ossificans progressiva (FOP) is a rare autosomal dominant disabling disorder characterized by progressive ossification of skeletal muscle, fascia, tendons, and ligaments. These conditions manifest phenotypic overlap in the ossification of tendons and ligaments. We describe herein a patient with DISH, exhibiting heterotopic ossification of the posterior longitudinal ligament where clinical whole exome sequencing identified a variant within ACVR1, a gene implicated in FOP. This variant, p.K400E, is a novel variant, not identified previously, and occurs in a highly conserved region across orthologs. We used sequence-based predicative algorithms, molecular modeling, and molecular dynamics simulations, to test the potential for p.K400E to alter the structure and dynamics of ACVR1. We applied the same modeling and simulation methods to established FOP variants, to identify the detailed effects that they have on the ACVR1 protein, as well as to act as positive controls against which the effects of p.K400E could be evaluated. Our in silico molecular analyses support p.K400E as altering the behavior of ACVR1. In addition, functional testing to measure the effect of this variant on BMP-pSMAD 1/5/8 target genes was carried out which revealed this variant to cause increased ID1 and Msx2 expression compared with the wild-type receptor. This analysis supports the potential for the variant of uncertain significance to contribute to the patient's phenotype.

4.
Medicina (Kaunas) ; 55(5)2019 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-31096651

RESUMO

Background and objectives: Loeys-Dietz syndrome 3, also known as aneurysms--osteoarthritis syndrome, is an autosomal dominant genetic connective tissue disease caused by pathogenic variants in SMAD3, a transcription factor involved in TGF-ß signaling. This disorder is characterized by early-onset osteoarthritis and arterial aneurysms. Common features include scoliosis, uvula abnormalities, striae, and velvety skin. Materials and Methods: The pathogenicity of a variant of uncertain significance in the SMAD3 gene was evaluated (variant c.220C > T) through personalized protein informatics and molecular studies. Results: The case of a 44-year-old male, who was originally presumed to have Marfan syndrome, is presented. An expanded gene panel determined the probable cause to be a variant in SMAD3, c.220C > T (p.R74W). His case was complicated by a history of stroke, but his phenotype was otherwise characteristic for Loeys-Dietz syndrome 3. Conclusion: This case emphasizes the importance of comprehensive genetic testing to evaluate patients for connective tissue disorders, as well as the potential benefit of utilizing a protein informatics platform for the assessment of variant pathogenicity.


Assuntos
Síndrome de Loeys-Dietz/genética , Proteína Smad3/análise , Proteína Smad3/genética , Adulto , Genômica/métodos , Humanos , Síndrome de Loeys-Dietz/sangue , Masculino , Fenótipo , Proteína Smad3/sangue
5.
Am J Med Genet A ; 179(8): 1556-1564, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31099476

RESUMO

Biallelic pathogenic variants in AARS2, a gene encoding the mitochondrial alanyl-tRNA synthetase, result in a spectrum of findings ranging from infantile cardiomyopathy to adult-onset progressive leukoencephalopathy. In this article, we present three unrelated individuals with novel compound heterozygous pathogenic AARS2 variants underlying diverse clinical presentations. Patient 1 is a 51-year-old man with adult-onset progressive cognitive, psychiatric, and motor decline and leukodystrophy. Patient 2 is a 34-year-old man with childhood-onset progressive tremor followed by the development of polyneuropathy, ataxia, and mild cognitive and psychiatric decline without leukodystrophy on imaging. Patient 3 is a 57-year-old woman with childhood-onset tremor and nystagmus which preceded dystonia, chorea, ataxia, depression, and cognitive decline marked by cerebellar atrophy and white matter disease. These cases expand the clinical heterogeneity of AARS2-related disorders, given that the first and third case represent some of the oldest known survivors of this disease, the second is adult-onset AARS2-related neurological decline without leukodystrophy, and the third is biallelic AARS2-related disorder involving a partial gene deletion.

6.
J Neuropathol Exp Neurol ; 78(5): 460-466, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30990878

RESUMO

Pathogenic hemizygous variants in the SH2D1A gene cause X-linked lymphoproliferative (XLP) syndrome, a rare primary immunodeficiency usually associated with fatal Epstein-Barr virus infection. Disease onset is typically in early childhood, and the average life expectancy of affected males is ∼11 years. We describe clinical, radiographic, neuropathologic, and genetic features of a 49-year-old man presenting with central nervous system vasculitis that was reminiscent of adult primary angiitis but which was unresponsive to treatment. The patient had 2 brothers; 1 died of aplastic anemia at age 13 and another died of diffuse large B-cell lymphoma in his sixties. Exome sequencing of the patient and his older brother identified a novel hemizygous variant in SH2D1A (c.35G>T, p.Ser12Ile), which encodes the signaling lymphocyte activation molecule (SLAM)-associated protein (SAP). Molecular modeling and functional analysis showed that this variant had decreased protein stability, similar to other pathogenic missense variants in SH2D1A. The family described in this report highlights the broadly heterogeneous clinical presentations of XLP and the accompanying diagnostic challenges in individuals presenting in adulthood. In addition, this report raises the possibility of a biphasic distribution of XLP cases, some of which may be mistaken for age-related malignancies and autoimmune conditions.

7.
Eur J Hum Genet ; 27(5): 738-746, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30679813

RESUMO

Determining pathogenicity of genomic variation identified by next-generation sequencing techniques can be supported by recurrent disruptive variants in the same gene in phenotypically similar individuals. However, interpretation of novel variants in a specific gene in individuals with mild-moderate intellectual disability (ID) without recognizable syndromic features can be challenging and reverse phenotyping is often required. We describe 24 individuals with a de novo disease-causing variant in, or partial deletion of, the F-box only protein 11 gene (FBXO11, also known as VIT1 and PRMT9). FBXO11 is part of the SCF (SKP1-cullin-F-box) complex, a multi-protein E3 ubiquitin-ligase complex catalyzing the ubiquitination of proteins destined for proteasomal degradation. Twenty-two variants were identified by next-generation sequencing, comprising 2 in-frame deletions, 11 missense variants, 1 canonical splice site variant, and 8 nonsense or frameshift variants leading to a truncated protein or degraded transcript. The remaining two variants were identified by array-comparative genomic hybridization and consisted of a partial deletion of FBXO11. All individuals had borderline to severe ID and behavioral problems (autism spectrum disorder, attention-deficit/hyperactivity disorder, anxiety, aggression) were observed in most of them. The most relevant common facial features included a thin upper lip and a broad prominent space between the paramedian peaks of the upper lip. Other features were hypotonia and hyperlaxity of the joints. We show that de novo variants in FBXO11 cause a syndromic form of ID. The current series show the power of reverse phenotyping in the interpretation of novel genetic variances in individuals who initially did not appear to have a clear recognizable phenotype.

8.
Mol Genet Genomic Med ; 7(3): e566, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30693671

RESUMO

BACKGROUND: Transient receptor potential cation channel subfamily V member 4 (TRPV4) is an ion channel permeable to Ca2+ that is sensitive to physical, hormonal, and chemical stimuli. This protein is expressed in many cell types, including osteoclasts, chondrocytes, and sensory neurons. As such, pathogenic variants of this gene are associated with skeletal dysplasias and neuromuscular disorders. Pathogenesis of these phenotypes is not yet completely understood, but it is known that genotype-phenotype correlations for TRPV4 pathogenic variants often are not present. METHODS: Newly characterized, suspected pathogenic variant in TRPV4 was analyzed using protein informatics and personalized protein-level molecular studies, genomic exome analysis, and clinical study. RESULTS: This statement is demonstrated in the family of our proband, a 47-year-old female having the novel c.2401A>G (p.K801E) variant of TRPV4. We discuss the common symptoms between the proband, her father, and her daughter, and compare her phenotype to known TRPV4-associated skeletal dysplasias. CONCLUSIONS: Protein informatics and molecular modeling are used to confirm the pathogenicity of the unique TRPV4 variant found in this family. Multiple data were combined in a comprehensive manner to give complete overall perspective on the patient disease and prognosis.


Assuntos
Simulação de Dinâmica Molecular , Mutação de Sentido Incorreto , Osteocondrodisplasias/genética , Fenótipo , Canais de Cátion TRPV/genética , Feminino , Humanos , Mutação com Perda de Função , Pessoa de Meia-Idade , Osteocondrodisplasias/patologia , Linhagem , Canais de Cátion TRPV/química , Canais de Cátion TRPV/metabolismo
10.
Artigo em Inglês | MEDLINE | ID: mdl-30478036

RESUMO

Although there has been considerable debate about whether paternal mitochondrial DNA (mtDNA) transmission may coexist with maternal transmission of mtDNA, it is generally believed that mitochondria and mtDNA are exclusively maternally inherited in humans. Here, we identified three unrelated multigeneration families with a high level of mtDNA heteroplasmy (ranging from 24 to 76%) in a total of 17 individuals. Heteroplasmy of mtDNA was independently examined by high-depth whole mtDNA sequencing analysis in our research laboratory and in two Clinical Laboratory Improvement Amendments and College of American Pathologists-accredited laboratories using multiple approaches. A comprehensive exploration of mtDNA segregation in these families shows biparental mtDNA transmission with an autosomal dominantlike inheritance mode. Our results suggest that, although the central dogma of maternal inheritance of mtDNA remains valid, there are some exceptional cases where paternal mtDNA could be passed to the offspring. Elucidating the molecular mechanism for this unusual mode of inheritance will provide new insights into how mtDNA is passed on from parent to offspring and may even lead to the development of new avenues for the therapeutic treatment for pathogenic mtDNA transmission.

11.
Artigo em Inglês | MEDLINE | ID: mdl-30187681

RESUMO

BACKGROUND: Beta-galactosidase-1 (GLB1) is a lysosomal hydrolase that is responsible for breaking down specific glycoconjugates, particularly GM1 (monosialotetrahexosylganglioside). Pathogenic variants in GLB1 cause two different lysosomal storage disorders: GM1 gangliosidosis and mucopolysaccharidosis type IVB. In GM1 gangliosidosis, decreased ß-galactosidase-1 enzymatic activity leads to the accumulation of GM1 gangliosides, predominantly within the CNS. We present a 22-month-old proband with GM1 gangliosidosis type II (late-infantile form) in whom a novel homozygous in-frame deletion (c.1468_1470delAAC, p.Asn490del) in GLB1 was detected. METHODS: We used an experimental protein structure of ß-galactosidase-1 to generate a model of the p.Asn490del mutant and performed molecular dynamic simulations to determine whether this mutation leads to altered ligand positioning compared to the wild-type protein. In addition, residual mutant enzyme activity in patient leukocytes was evaluated using a fluorometric assay. RESULTS: Molecular dynamics simulations showed the deletion to alter the catalytic site leading to misalignment of the catalytic residues and loss of collective motion within the model. We predict this misalignment will lead to impaired catalysis of ß-galactosidase-1 substrates. Enzyme assays confirmed diminished GLB1 enzymatic activity (~3% of normal activity) in the proband. CONCLUSIONS: We have described a novel, pathogenic in-frame deletion of GLB1 in a patient with GM1 gangliosidosis type II.

12.
13.
Mol Genet Genomic Med ; 6(5): 805-810, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30043523

RESUMO

BACKGROUND: Although the process of reclassification of a variant of uncertain significance can be complex, they are commonly detected through molecular testing. It often takes years before enough clinical data are acquired, and it can be costly and time-consuming to perform functional analysis of a single variant. It is important that other tools are developed to aid in clarifying how a specific genetic variant impacts a protein's function, and ultimately the health of the patient. METHODS: Two more newly characterized, suspected pathogenic variants in NBN and PTEN were analyzed through personalized protein modeling. Comparisons between the wild-type and altered protein were studied using simulations, genomic exome analysis, and clinic study. RESULTS: Modeling of the new NBN and PTEN protein structures suggested loss of essential domains important for normal enzymatic function for these personalized genomic examples which matched the clinical findings. CONCLUSION: The defects detected through modeling were consistent with the expected clinical effect. Personalized protein modeling is another tool for determination of correct variant classification, which can become further useful through construction of deposition archive.

14.
Hum Genome Var ; 5: 15, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30002862

RESUMO

We report two female patients with focal segmental glomerulosclerosis and chronic kidney disease. The first patient was found to have a heterozygous, de novo, pathogenic variant in COL4A5 (c.141+1G>A, IVS2+1G>A), which is associated with Alport syndrome. The second patient was found to have a heterozygous, likely pathogenic variant in COL4A4 (c.2842G>T). Both these variants in COL4A5 and COL4A4 are novel, and they were detected using whole exome sequencing and gene panel testing, respectively. Additionally, we discuss the complexities of diagnosis in such cases and the benefits of using the abovementioned diagnostic approaches.

15.
Mol Genet Metab Rep ; 15: 11-14, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30023283

RESUMO

Sialidosis is an autosomal recessive lysosomal storage disease caused by pathogenic variants in NEU1 which encodes lysosomal sialidase (neuraminidase 1). Lysosomal neuraminidase catalyzes the removal of terminal sialic acid molecules from glycolipids, glycoproteins and oligosaccharides. Sialidosis is classified into two types, based on phenotype and age of onset. Patients with the milder type 1 typically present late, usually in the second or third decade, with myoclonus, ataxia and visual defects. Type 2 is more severe and presents earlier with coarse facial features, developmental delay, hepatosplenomegaly and dysostosis multiplex. Presentation and severity of the disease are related to whether lysosomal sialidase is inactive or there is some residual activity. Diagnosis is suspected based on clinical features and increased urinary bound sialic acid excretion and confirmed by genetic testing showing pathogenic variants in NEU1. We report a patient with type 1 sialidosis who presented mainly with ataxia and both generalized and myoclonic seizures but no visual involvement. Whole exome sequencing of the proband detected compound heterozygous likely pathogenic variants (S182G and G227R) in NEU1.

16.
J Pediatr Genet ; 7(2): 83-85, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29707410

RESUMO

Marfan syndrome and dominant ectopia lentis are part of type 1 fibrillinopathies that are caused by FBN1 pathogenic variants. Making a diagnosis could be challenging due to the clinical overlap between these disorders. The revised Ghent criteria used for Marfan syndrome diagnosis helped in resolving some of the confusion, especially in younger children. We report on a case of bilateral ectopia lentis in a 2-year-old child with a normal echocardiogram. FBN1 sequencing revealed a novel likely pathogenic variant described as c.385T > A (p.Cys129Ser). The patient's father also has a history of bilateral ectopia lentis and his genetic analysis detected the same FBN1 variant as the proband.

17.
Fam Cancer ; 2018 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-29721668

RESUMO

A growing number of physicians will interact with genetic test results as testing becomes more commonplace. While variants of uncertain significance can complicate results, it is equally important that physicians understand how to incorporate these results into clinical care. An online survey was created to assess physician self-reported comfort level with genetics and variants of uncertain significance. Physicians were asked to respond to three case examples involving genetic test results. The survey was sent to 488 physicians at Mayo Clinic FL on 8/16/2017. Physicians from all specialties were invited to participate. A total of 92 physicians responded to the survey. Only 13/84 (14.6%) responded to all three case examples with the answer deemed "most correct" by review of literature. Physicians that specialized in cancer were more likely to answer questions appropriately (P = .02). Around half (39/84) of the physicians incorrectly defined a variant of uncertain significance (VUS). Over 75% made a recommendation for genetic testing that was not warranted. Many physicians have never received formal genetics training; however, they will be expected to provide an accurate explanation of the genetic test results and subsequent evidence-based medical management recommendations. These results demonstrate that a substantial proportion of physicians lack a true understanding of the implications a VUS. Utilization of supplemental genetics training programs coupled with increase awareness of genetic services may help to improve patient care.

18.
Case Rep Genet ; 2018: 6780494, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29796325

RESUMO

We present a 43-year-old man with aortic root dilation, mitral valve prolapse, and marfanoid appearance, who presented with acute onset left leg pain. He underwent a Doppler ultrasound that revealed left popliteal artery aneurysm with thrombus. CT angiogram showed bilateral popliteal artery aneurysms. After repairing of his left popliteal artery aneurysm, he was sent for genetic evaluation. He was diagnosed with Marfan syndrome (MFS) based on the revised Ghent criteria and then underwent FBN1 sequencing and deletion/duplication analysis, which detected a novel pathogenic variant in gene FBN1, denoted by c.5872 T>A (p.Cys1958Ser). MFS is a connective tissue disorder with an autosomal dominant inheritance due to pathogenic variants in FBN1 that encodes Fibrillin-1, a major element of the extracellular matrix, and connective tissue throughout the body. MFS involves multiple systems, most commonly the cardiovascular, musculoskeletal, and visual systems. In our case we present a rare finding of bilateral popliteal artery aneurysms in a male patient with MFS.

19.
Neurol Neurochir Pol ; 52(3): 386-389, 2018 May - Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29680161

RESUMO

AIM OF THE STUDY: To describe a family with primary familial brain calcification (PFBC) due to SLC20A2 variant showing possible genetic anticipation. MATERIALS AND METHODS: We conducted historical, genealogical, clinical, and radiologic studies of a family with PFBC. Clinical evaluations including neurological examination and head computed tomography (CT) scans of a proband and her father were performed. They provided additional information regarding other family members. To identify a causative gene variant, we performed whole-exome sequencing for the proband followed by segregation analysis in other affected members using direct sequencing. RESULTS: In this family, nine affected members were identified over four generations. The proband suffered from chronic daily headache including thunderclap headache. We identified an SLC20A2 (c.509delT, p.(Leu170*)) variant in three affected members over three generations. Interestingly, the age of onset became younger as the disease passed through successive generations, suggestive of genetic anticipation. CONCLUSIONS AND CLINICAL IMPLICATIONS: For clinical purpose, it is important to consider thunderclap headache and genetic anticipation in PFBC caused by SLC20A2 variants. Further investigation is required to validate our observation.

20.
J Am Soc Nephrol ; 29(7): 1849-1858, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29654216

RESUMO

Background For many patients with kidney failure, the cause and underlying defect remain unknown. Here, we describe a novel mechanism of a genetic order characterized by renal Fanconi syndrome and kidney failure.Methods We clinically and genetically characterized members of five families with autosomal dominant renal Fanconi syndrome and kidney failure. We performed genome-wide linkage analysis, sequencing, and expression studies in kidney biopsy specimens and renal cells along with knockout mouse studies and evaluations of mitochondrial morphology and function. Structural studies examined the effects of recognized mutations.Results The renal disease in these patients resulted from monoallelic mutations in the gene encoding glycine amidinotransferase (GATM), a renal proximal tubular enzyme in the creatine biosynthetic pathway that is otherwise associated with a recessive disorder of creatine deficiency. In silico analysis showed that the particular GATM mutations, identified in 28 members of the five families, create an additional interaction interface within the GATM protein and likely cause the linear aggregation of GATM observed in patient biopsy specimens and cultured proximal tubule cells. GATM aggregates-containing mitochondria were elongated and associated with increased ROS production, activation of the NLRP3 inflammasome, enhanced expression of the profibrotic cytokine IL-18, and increased cell death.Conclusions In this novel genetic disorder, fully penetrant heterozygous missense mutations in GATM trigger intramitochondrial fibrillary deposition of GATM and lead to elongated and abnormal mitochondria. We speculate that this renal proximal tubular mitochondrial pathology initiates a response from the inflammasome, with subsequent development of kidney fibrosis.

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