Doublecortin, encoded by the
gene, plays a crucial role in the neuronal migration process during brain development. Pathogenic variants of the
gene are the major causes of the "lissencephaly (LIS) ...spectrum", which comprehends a milder phenotype like Subcortical Band Heterotopia (SBH) in heterozygous female subjects. We performed targeted sequencing in three unrelated female cases with SBH. We identified three DCX-related variants: a novel missense (c.601A>G: p.Lys201Glu), a novel nonsense (c.210C>G: p.Tyr70*), and a previously identified nonsense (c.907C>T: p.Arg303*) variant. The novel c.601A>G: p.Lys201Glu variant shows a mother-daughter transmission pattern across four generations. The proband exhibits focal epilepsy and achieved seizure freedom with a combination of oxcarbazepine and levetiracetam. All other affected members have no history of epileptic seizures. Brain MRIs of the affected members shows predominant fronto-central SBH with mixed pachygyria on the overlying cortex. The two nonsense variants were identified in two unrelated probands with SBH, severe drug-resistant epilepsy and intellectual disability. These novel DCX variants further expand the genotypic-phenotypic correlations of lissencephaly spectrum disorders. Our documented phenotypic descriptions of three unrelated families provide valuable insights and stimulate further discussions on DCX-SBH cases.
Abstract Parkinson’s Disease (PD) is the most common form of degenerative parkinsonism with a prevalence of 1% of those older than 65 years. PD is characterized by the combination of slowness of ...movement (bradykinesia), muscular rigidity, resting tremor and postural instability. Recently, using a genome-wide linkage analysis and exome sequencing, a group identified a candidate gene ( CHCHD2 ) in a large Japanese family with autosomal dominant Parkinson’s disease. The aim of this study was to evaluate the presence of CHCHD2 mutations in a cohort of 165 familial patients with clinically diagnosed PD and 200 control subjects from South Italy. No mutations in CHCHD2 were found in our 165 PD patients. This result, suggesting that CHCHD2 mutations might not be common cause of PD in South Italy.
Ferritin, the major iron storage protein, performs its essential functions in the cytoplasm, nucleus and mitochondria. The variable assembly of 24 subunits of the Heavy (H) and Light (L) type ...composes the cytoplasmic molecule. In humans, two distinct genes code these subunits, both belonging to complex multigene families. Until now, one H gene has been identified with the coding sequence interrupted by three introns and more than 20 intronless copies widely dispersed on different chromosomes. Two of the intronless genes are actively transcribed in a tissue-specific manner. Herein, we report that FTH1P3, another intronless pseudogene, is transcribed. FTH1P3 transcript was detected in several cell lines and tissues, suggesting that its transcription is ubiquitary, as it happens for the parental ferritin H gene. Moreover, FTH1P3 expression is positively regulated during the cell differentiation process.
GLUT1 Deficiency Syndrome (GLUT1-DS) is a rare and potentially treatable neurometabolic condition, caused by a reduced glucose transport into the brain and clinically characterized by an epileptic ...encephalopathy with movement disorders. A wide inter-intrafamilial phenotypic variability has been reported. Very-long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is an inherited metabolic disorder of mitochondrial long-chain fatty acid oxidation (FAO) with also a variable age of onset and clinical presentation including cardiomyopathy, hypoketotic hypoglycemia, and liver disease. Sometimes, VLCAD manifests later with a prevalent muscle involvement characterized by exercise intolerance and recurrent rhabdomyolysis. We report a 40-year-old man with mild mental retardation and sporadic choreo-athetoid movements, who complained of recurrent episodes of rhabdomyolysis triggered by exercise or fasting since his twenties. His 15-year-old son had a psychomotor developmental delay with episodes of drowsiness mainly at fasting and exercise-induced choreo-athetoid movements but no history of pigmenturia. Clinical and laboratory findings in the son suggested a diagnosis of GLUT1-DS confirmed by
SCL2A1
genetic analysis that revealed a heterozygous mutation c.997C>T (p.R333W) that was also found in the proband. However, the presence in the latter of recurrent exercise-induced rhabdomyolysis, never reported in GLUT1-DS, implied a second metabolic disorder. Increased plasma C14:1-carnitine levels and the identification of two known heterozygous mutations c. 553G>A (p.G185S) and c.1153C>T (p.R385W) in
ACADVL
confirmed the additional diagnosis of VLCAD deficiency in the proband. Nowadays, there is an increasing evidence of “double trouble” cases of genetic origin. Consequently, when atypical features accompany a known phenotype, associated comorbidities should be considered.
Early onset has been implicated in clinical severity of sporadic Parkinson's Disease (PD) in many populations. PD onset is an important prognostic factor since the continuing neurodegeneration of PD ...is associated with cognitive deficit. The aim of this study is to analyze the age at onset (AAO) and cognitive deficit of PD in regards of the APOE gene. We investigated the AAO in a sample of 393 sporadic Parkinson's cases from Southern Italy. The admixture analysis highlighted the presence of two onset subgroups in our PD sample. Our analysis of early onset Parkinson's disease confirms the effect on more severe memory deficit in subjects with anticipated onset mediated by the APOE e4 (beta = −0.47; p = 0.02). Our study implicates the effect of e4 allele in susceptibility to cognitive symptoms in late onset PD. Even though our results are preliminary the APOE e4 allele may represent a moderating factor for cognitive deficit and anticipation in late onset PD patients.
•The best fitting model of age at onset of Parkinson's Disease is composed by two normal distributions with equal variance.•Early and late onset Parkinson’s Disease distributions have means at 48.5±7.1 and 63.5±7.1 respectively.•The FMM incorporating the APOE genetic effect in late onset Parkinson confirms the correlation between age at onset and memory deficit.
Phospholipase A2-associated neurodegeneration (PLAN), a syndrome of Neurodegeneration with Brain Iron Accumulation (NBIA), is an autosomal recessive disorder caused by mutations in PLA2G6 gene. This ...gene encodes a calcium-independent group VI phospholipase A2 (iPLA-VI) critical in cell membrane homeostasis.
PLAN syndrome encompasses a group of phenotypes with a different age of onset: classic infantile neuroaxonal dystrophy (INAD), atypical neuroaxonal dystrophy of childhood-onset (atypical NAD) and adult-onset PLA2G6-related dystonia-parkinsonism (PARK14).
INAD is a severe progressive psychomotor disorder characterized by the presence of axonal spheroids throughout the central and peripheral nervous system. Here we report clinical, genetic and histopathological findings of an INAD consanguineous-family from Senegal. Sanger sequencing analysis revealed a new homozygous PLA2G6-mutation in the proband (c.1483C>T) and the co-segregation of the mutation in this family.
Electron microscopy on skin biopsy showed degenerated axons confirming the phenotype.
This study contributes to enrich the landscape of PLA2G6-associated INAD mutations and enforce the genotype-phenotype correlation.
•We describe a 5-years old patient with typical INAD coming from a Senegal's consanguineous family.•Genetic analysis revealed a new PLA2G6-mutation and the co-segregation of the mutation in this family.•The iPLA2 β is not present in patient's cells as suggested by the nonsense-mediated mRNA decay at the RNA level.•This study enriches the landscape of PLA2G6-associated INAD mutations confirming the genotype-phenotype correlation.
Objectives
Myotonia is a clinical sign typical of a group of skeletal muscle channelopathies, the non‐dystrophic myotonias. These disorders are electrophysiologically characterized by altered ...membrane excitability, due to specific genetic variants in known causative genes (CLCN1 and SCN4A). Juvenile Myoclonic Epilepsy (JME) is an epileptic syndrome identified as idiopathic generalized epilepsy, its genetics is complex and still unclarified. The co‐occurrence of these two phenotypes is rare and the causes likely have a genetic background. In this study, we have genetically investigated an Italian family in which co‐segregates myotonia, JME, or abnormal EEG without seizures was observed.
Methods
All six individuals of the family, 4 affected and 2 unaffected, were clinically evaluated; EMG and EEG examinations were performed. For genetic testing, Exome Sequencing was performed for the six family members and Sanger sequencing was used to confirm the candidate variant.
Results
Four family members, the mother and three siblings, were affected by myotonia. Moreover, EEG recordings revealed interictal generalized sharp‐wave discharges in all affected individuals, and two siblings were affected by JME. All four affected members share the same identified variant, c.644 T > C, p.Ile215Thr, in SCN4A gene. Variants that could account for the epileptic phenotype alone, separately from the myotonic one, were not identified.
Significance
These results provide supporting evidence that both myotonic and epileptic phenotypes could share a common genetic background, due to variants in SCN4A gene. SCN4A pathogenic variants, already known to be causative of myotonia, likely increase the susceptibility to epilepsy in our family.
Plain Language Summary
This study analyzed all members of an Italian family, in which the mother and three siblings had myotonia and epilepsy. Genetic analysis allowed to identify a variant in the SCN4A gene, which appears to be the cause of both clinical signs in this family.
The hotspot AKT1E17K mutation in the pleckstrin homology domain of AKT1 occurs in approximately 0.6-2% of human lung cancers. Recently, we have demonstrated that AKT1E17K transforms immortalized ...human bronchial cells. Here by use of a transgenic Cre-inducible murine strain in the wild type Rosa26 (R26) locus (R26-AKT1E17K mice) we demonstrate that AKT1E17K is a bona-fide oncogene and plays a role in the development of lung cancer in vivo. In fact, we report that mutant AKT1E17K induces bronchial and/or bronchiolar hyperplastic lesions in murine lung epithelium, which progress to frank carcinoma at very low frequency, and accelerates tumor formation induced by chemical carcinogens. In conclusion, AKT1E17K induces hyperplasia of mouse lung epithelium in vivo and cooperates with urethane to induce the fully malignant phenotype.
Fragile X-associated tremor/ataxia syndrome is a late-onset neurodegenerative disorder that affects about 40% of carriers of CGG-repeat expansions in the premutation range within the fragile X gene ...(FMR1). Main clinical features include intention tremor, cerebellar ataxia, and parkinsonism. Recently, great emphasis on the deposition of soluble aggregates produced by a RAN translation process, as main pathogenic mechanism, has been given. These aggregates contain a small protein with a polyglycine stretch on the aminoterminal end named FMRpolyG and, so far, have been isolated and characterized in drosophila and mouse models, in post mortem brain of fragile X-associated tremor/ataxia syndrome patients, in fibroblasts of fragile primary ovarian insufficiency patients, but never in fibroblasts from a fragile X-associated tremor/ataxia living patients. In adult carriers the syndrome is frequently misdiagnosed due to the lack of specific markers.
We standardized immunocytochemistry, immunoprecipitation and western blot procedures to study and biochemically characterize the FMRpolyG protein in fibroblasts from human skin biopsy.
We demonstrate for the first time, in fibroblasts from a patient affected by Fragile X-associated tremor/ataxia syndrome, the presence ex vivo of inclusions consisting of FMRpolyG- Hsp70 soluble aggregates.
These observations can pave the way to develop a cellular model for studying ex vivo and in vitro the mechanisms involved in the production of FMRpolyG aggregates, their toxicity, and the role of the FMRpolyG-Hsp70 interaction in the pathogenesis of fragile X-associated tremor/ataxia syndrome.
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