scholarly journals Novel deep intronic mutation in PLA2G6 causing early-onset Parkinson’s disease with brain iron accumulation through pseudo-exon activation

Neurogenetics ◽  
2021 ◽  
Author(s):  
Chiara Cavestro ◽  
Celeste Panteghini ◽  
Chiara Reale ◽  
Alessia Nasca ◽  
Silvia Fenu ◽  
...  
Keyword(s):  
Early Onset ◽  
Cerebellar Atrophy ◽  
Iron Accumulation ◽  
Brain Iron ◽  
Causative Gene ◽  
Coding Regions ◽  
Aberrant Transcript ◽  
Pathogenic Variants ◽  
Intronic Mutation ◽  
Mrna Analysis

AbstractPLA2G6 is the causative gene for a group of autosomal recessive neurodegenerative disorders known as PLA2G6-associated neurodegeneration (PLAN). We present a case with early-onset parkinsonism, ataxia, cognitive decline, cerebellar atrophy, and brain iron accumulation. Sequencing of PLA2G6 coding regions identified only a heterozygous nonsense variant, but mRNA analysis revealed the presence of an aberrant transcript isoform due to a novel deep intronic variant (c.2035-274G > A) leading to activation of an intronic pseudo-exon. These results expand the genotypic spectrum of PLAN, showing the paramount importance of detecting possible pathogenic variants in deep intronic regions in undiagnosed patients.

scholarly journals A comprehensive phenotypic characterization of a whole-body Wdr45 knock-out mouse

2021 ◽  
Author(s):  
Caroline A. Biagosch ◽  
Silvia Vidali ◽  
Michael Faerberboeck ◽  
Svenja-Viola Hensler ◽  
Lore Becker ◽  
...  
Keyword(s):  
Mouse Model ◽  
Iron Accumulation ◽  
Whole Body ◽  
Phenotypic Characterization ◽  
Brain Iron ◽  
Exon 2 ◽  
Knock Out ◽  
Pathogenic Variants ◽  
Robust Model

AbstractPathogenic variants in the WDR45 (OMIM: 300,526) gene on chromosome Xp11 are the genetic cause of a rare neurological disorder characterized by increased iron deposition in the basal ganglia. As WDR45 encodes a beta-propeller scaffold protein with a putative role in autophagy, the disease has been named Beta-Propeller Protein-Associated Neurodegeneration (BPAN). BPAN represents one of the four most common forms of Neurodegeneration with Brain Iron Accumulation (NBIA). In the current study, we generated and characterized a whole-body Wdr45 knock-out (KO) mouse model. The model, developed using TALENs, presents a 20-bp deletion in exon 2 of Wdr45. Homozygous females and hemizygous males are viable, proving that systemic depletion of Wdr45 does not impair viability and male fertility in mice. The in-depth phenotypic characterization of the mouse model revealed neuropathology signs at four months of age, neurodegeneration progressing with ageing, hearing and visual impairment, specific haematological alterations, but no brain iron accumulation. Biochemically, Wdr45 KO mice presented with decreased complex I (CI) activity in the brain, suggesting that mitochondrial dysfunction accompanies Wdr45 deficiency. Overall, the systemic Wdr45 KO described here complements the two mouse models previously reported in the literature (PMIDs: 26,000,824, 31,204,559) and represents an additional robust model to investigate the pathophysiology of BPAN and to test therapeutic strategies for the disease.

Screening of BRCA1/2 deep intronic regions by targeted gene sequencing identifies the first germline BRCA1 variant causing pseudoexon activation in a patient with breast/ovarian cancer

2018 ◽  
Vol 56 (2) ◽  
pp. 63-74 ◽  
Author(s):  
Gemma Montalban ◽  
Sandra Bonache ◽  
Alejandro Moles-Fernández ◽  
Alexandra Gisbert-Beamud ◽  
Anna Tenés ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Rare Variants ◽  
Genetic Diagnosis ◽  
Gene Sequencing ◽  
Functional Protein ◽  
Coding Regions ◽  
Aberrant Transcript ◽  
Pathogenic Variants ◽  
Novel Transcript ◽  
Targeted Gene Sequencing

BackgroundGenetic analysis of BRCA1 and BRCA2 for the diagnosis of hereditary breast and ovarian cancer (HBOC) is commonly restricted to coding regions and exon-intron boundaries. Although germline pathogenic variants in these regions explain about ~20% of HBOC cases, there is still an important fraction that remains undiagnosed. We have screened BRCA1/2 deep intronic regions to identify potential spliceogenic variants that could explain part of the missing HBOC susceptibility.MethodsWe analysed BRCA1/2 deep intronic regions by targeted gene sequencing in 192 high-risk HBOC families testing negative for BRCA1/2 during conventional analysis. Rare variants (MAF <0.005) predicted to create/activate splice sites were selected for further characterisation in patient RNA. The splicing outcome was analysed by RT-PCR and Sanger sequencing, and allelic imbalance was also determined when heterozygous exonic loci were present.ResultsA novel transcript was detected in BRCA1 c.4185+4105C>T variant carrier. This variant promotes the inclusion of a pseudoexon in mature mRNA, generating an aberrant transcript predicted to encode for a non-functional protein. Quantitative and allele-specific assays determined haploinsufficiency in the variant carrier, supporting a pathogenic effect for this variant. Genotyping of 1030 HBOC cases and 327 controls did not identify additional carriers in Spanish population.ConclusionScreening of BRCA1/2 intronic regions has identified the first BRCA1 deep intronic variant associated with HBOC by pseudoexon activation. Although the frequency of deleterious variants in these regions appears to be low, our study highlights the importance of studying non-coding regions and performing comprehensive RNA assays to complement genetic diagnosis.

Early-onset neurodegeneration with brain iron accumulation due to PANK2 mutation

2012 ◽  
Vol 34 (6) ◽  
pp. 536-538 ◽  
Author(s):  
Daniela Rossi ◽  
Elisa De Grandis ◽  
Chiara Barzaghi ◽  
Monica Mascaretti ◽  
Barbara Garavaglia ◽  
...  
Keyword(s):  
Early Onset ◽  
Iron Accumulation ◽  
Brain Iron

Neurodegeneration with brain iron accumulation type 4 by mutation in the C19orf12 gene: first time found in adolescent of Russian origin

2013 ◽  
Vol 44 (02) ◽  
Author(s):  
E Giagkou ◽  
S Lutz ◽  
U Schara ◽  
K Becker ◽  
C Möller-Hartmann
Keyword(s):  
Iron Accumulation ◽  
Brain Iron ◽  
First Time

Psychotic Disorder in Neurodegeneration with Brain Iron Accumulation

2016 ◽  
Vol 10 (3) ◽  
pp. 178-180
Author(s):  
Menekse Sila Yazar ◽  
Nurhan Fistikci ◽  
Ozlem Devrim Balaban ◽  
Nezih Eradamlar ◽  
Latif Alpkan
Keyword(s):  
Psychotic Disorder ◽  
Iron Accumulation ◽  
Brain Iron

scholarly journals Patients With Extreme Early Onset Juvenile Huntington Disease Can Have Delays in Diagnosis: A Case Report and Literature Review

2021 ◽  
Vol 8 ◽  
pp. 2329048X2110361
Author(s):  
Ashley A. Moeller ◽  
Marcia V. Felker ◽  
Jennifer A. Brault ◽  
Laura C. Duncan ◽  
Rizwan Hamid ◽  
...  
Keyword(s):  
Symptom Onset ◽  
Huntington Disease ◽  
Early Onset ◽  
Trinucleotide Repeat ◽  
Cerebellar Atrophy ◽  
Cag Repeats ◽  
Ataxic Gait ◽  
Repeat Expansions ◽  
Delays In Diagnosis ◽  
Juvenile Huntington Disease

Huntington disease (HD) is caused by a pathologic cytosine-adenine-guanine (CAG) trinucleotide repeat expansion in the HTT gene. Typical adult-onset disease occurs with a minimum of 40 repeats. With more than 60 CAG repeats, patients can have juvenile-onset disease (jHD), with symptom onset by the age of 20 years. We report a case of a boy with extreme early onset, paternally inherited jHD, with symptom onset between 18 and 24 months. He was found to have 250 to 350 CAG repeats, one of the largest repeat expansions published to date. At initial presentation, he had an ataxic gait, truncal titubation, and speech delay. Magnetic resonance imaging showed cerebellar atrophy. Over time, he continued to regress and became nonverbal, wheelchair-bound, gastrostomy-tube dependent, and increasingly rigid. His young age at presentation and the ethical concerns regarding HD testing in minors delayed his diagnosis.

scholarly journals High likelihood of actionable pathogenic variant detection in breast cancer genes in women with very early onset breast cancer

2021 ◽  
pp. jmedgenet-2020-107347
Author(s):  
D Gareth Evans ◽  
Elke Maria van Veen ◽  
Helen J Byers ◽  
Sarah J Evans ◽  
George J Burghel ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Early Onset ◽  
Ductal Carcinoma ◽  
Cancer Genes ◽  
Early Onset Breast Cancer ◽  
Younger Women ◽  
Pathogenic Variants ◽  
Younger Age ◽  
Predisposition Genes

BackgroundWhile the likelihood of identifying constitutional breast cancer-associated BRCA1, BRCA2 and TP53 pathogenic variants (PVs) increases with earlier diagnosis age, little is known about the correlation with age at diagnosis in other predisposition genes. Here, we assessed the contribution of known breast cancer-associated genes to very early onset disease.MethodsSequencing of BRCA1, BRCA2, TP53 and CHEK2 c.1100delC was undertaken in women with breast cancer diagnosed ≤30 years. Those testing negative were screened for PVs in a minimum of eight additional breast cancer-associated genes. Rates of PVs were compared with cases ≤30 years from the Prospective study of Outcomes in Sporadic vs Hereditary breast cancer (POSH) study.ResultsTesting 379 women with breast cancer aged ≤30 years identified 75 PVs (19.7%) in BRCA1, 35 (9.2%) in BRCA2, 22 (5.8%) in TP53 and 2 (0.5%) CHEK2 c.1100delC. Extended screening of 184 PV negative women only identified eight additional actionable PVs. BRCA1/2 PVs were more common in women aged 26–30 years than in younger women (p=0.0083) although the younger age group had rates more similar to those in the POSH cohort. Out of 26 women with ductal carcinoma in situ (DCIS) alone, most were high-grade and 11/26 (42.3%) had a PV (TP53=6, BRCA2=2, BRCA1=2, PALB2=1). This PV yield is similar to the 61 (48.8%) BRCA1/2 PVs identified in 125 women with triple-negative breast cancer. The POSH cohort specifically excluded pure DCIS which may explain lower TP53 PV rates in this group (1.7%).ConclusionThe rates of BRCA1, BRCA2 and TP53 PVs are high in very early onset breast cancer, with limited benefit from testing of additional breast cancer-associated genes.

scholarly journals Genetic and immunologic findings in children with recurrent aphthous stomatitis with systemic inflammation

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Martina Girardelli ◽  
Erica Valencic ◽  
Valentina Moressa ◽  
Roberta Margagliotta ◽  
Alessandra Tesser ◽  
...  
Keyword(s):  
Clinical Diagnosis ◽  
Systemic Inflammation ◽  
Lupus Erythematosus ◽  
Early Onset ◽  
Disease Onset ◽  
Recurrent Aphthous Stomatitis ◽  
Aphthous Stomatitis ◽  
Monogenic Disorders ◽  
Pathogenic Variants ◽  
Targeted Treatments

Abstract Background Recurrent aphthous stomatitis with systemic signs of inflammation can be encountered in inflammatory bowel disease, Behçet’s disease (BD), Systemic Lupus Erythematosus (SLE). In addition, it has been proposed that cases with very early onset in childhood can be underpinned by rare monogenic defects of immunity, which may require targeted treatments. Thus, subjects with early onset recurrent aphthous stomatitis receiving a clinical diagnosis of BD-like or SLE-like disease may deserve a further diagnostic workout, including immunologic and genetic investigations. Objective To investigate how an immunologic, genetic and transcriptomics assessment of interferon inflammation may improve diagnosis and care in children with recurrent aphthous stomatitis with systemic inflammation. Methods Subjects referred to the pediatric rheumatologist for recurrent aphthous stomatitis associated with signs of systemic inflammation from January 2015 to January 2020 were enrolled in the study and underwent analysis of peripheral lymphocyte subsets, sequencing of a 17-genes panel and measure of interferon score. Results We enrolled 15 subjects (12 females, median age at disease onset 4 years). The clinical diagnosis was BD in 8, incomplete BD in 5, BD/SLE overlap in 1, SLE in 1. Pathogenic genetic variants were detected in 3 patients, respectively 2 STAT1 gain of function variants in two patients classified as BD/SLE overlap and SLE, and 1 TNFAIP3 mutation (A20 haploinsufficiency) in patients with BD. Moreover 2 likely pathogenic variants were identified in DNASE1L3 and PTPN22, both in patients with incomplete BD. Interferon score was high in the two patients with STAT1 GOF mutations, in the patient with TNFAIP3 mutation, and in 3 genetic-negative subjects. In two patients, the treatment was modified based on genetic results. Conclusions Although recurrent aphthous stomatitis associated with systemic inflammation may lead to a clinical diagnosis of BD or SLE, subjects with early disease onset in childhood deserve genetic investigation for rare monogenic disorders. A wider genetic panel may help disclosing the genetic background in the subset of children with increased interferon score, who tested negative in this study.

scholarly journals Bi-allelic variants in MTMR5/SBF1 cause Charcot-Marie-Tooth type 4B3 featuring mitochondrial dysfunction

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Beatrice Berti ◽  
Giovanna Longo ◽  
Francesco Mari ◽  
Stefano Doccini ◽  
Ilaria Piccolo ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Mitochondrial Dysfunction ◽  
Early Onset ◽  
Integrated Approach ◽  
Compound Heterozygous ◽  
Charcot Marie Tooth ◽  
Charcot Marie Tooth Disease ◽  
Pathogenic Variants ◽  
First Case ◽  
Spine Mri

Abstract Background Charcot-Marie-Tooth disease (CMT) type 4B3 (CMT4B3) is a rare form of genetic neuropathy associated with variants in the MTMR5/SBF1 gene. MTMR5/SBF1 is a pseudophosphatase predicted to regulate endo-lysosomal trafficking in tandem with other MTMRs. Although almost ubiquitously expressed, pathogenic variants primarily impact on the peripheral nervous system, corroborating the involvement of MTMR5/SBF1 and its molecular partners in Schwann cells-mediated myelinization. Case presentation We report a case of severe CMT4B3 characterized by early-onset motor and axonal polyneuropathy in an Italian child in absence of any evidence of brain and spine MRI abnormalities or intellectual disability and with a biochemical profile suggestive of mitochondrial disease. Using an integrated approach combining both NGS gene panels and WES analysis, we identified two novel compound heterozygous missense variants in MTMR5/SBF1 gene, p.R763H (c.2291G > A) and p.G1064E (c.3194G > A). Studies in muscle identified partial defects of oxidative metabolism. Conclusion We describe the first case of an early onset severe polyneuropathy with motor and axonal involvement, due to recessive variants in the MTMR5/SBF1 gene, with no evidence of brain and spine MRI abnormalities, intellectual disability, no clinical and neurophysiological evidences of distal sensory impairment, and rapid neuromuscular deterioration. This report suggests that MTMR5/SBF1 should be considered in cases of infantile-onset CMT with secondary mitochondrial dysfunction.

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