Acetazolamide Improves Episodic Ataxia in a Patient with Non-Verbal Autism and Paroxysmal Dyskinesia Due To PRRT2 Biallelic Variants.
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SUBMITTER: Martorell L
PROVIDER: S-EPMC9547142 | biostudies-literature | 2022 Oct
REPOSITORIES: biostudies-literature
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Acetazolamide Improves Episodic Ataxia in a Patient with Non-Verbal Autism and Paroxysmal Dyskinesia Due To <i>PRRT2</i> Biallelic Variants.
Martorell Loreto L Macaya Alfons A Pérez-Dueñas Belén B Ortigoza-Escobar Juan Darío JD
Movement disorders clinical practice 20220822 7
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Project description:ObjectiveThe proline-rich transmembrane protein (PRRT2) gene was recently identified using exome sequencing as the cause of autosomal dominant paroxysmal kinesigenic dyskinesia (PKD) with or without infantile convulsions (IC) (PKD/IC syndrome). Episodic neurologic disorders, such as epilepsy, migraine, and paroxysmal movement disorders, often coexist and are thought to have a shared channel-related etiology. To investigate further the frequency, spectrum, and phenotype of PRRT2 mutations, we analyzed this gene in 3 large series of episodic neurologic disorders with PKD/IC, episodic ataxia (EA), and hemiplegic migraine (HM).MethodsThe PRRT2 gene was sequenced in 58 family probands/sporadic individuals with PKD/IC, 182 with EA, 128 with HM, and 475 UK and 96 Asian controls.ResultsPRRT2 genetic mutations were identified in 28 out of 58 individuals with PKD/IC (48%), 1/182 individuals with EA, and 1/128 individuals with HM. A number of loss-of-function and coding missense mutations were identified; the most common mutation found was the p.R217Pfs*8 insertion. Males were more frequently affected than females (ratio 52:32). There was a high proportion of PRRT2 mutations found in families and sporadic cases with PKD associated with migraine or HM (10 out of 28). One family had EA with HM and another large family had typical HM alone.ConclusionsThis work expands the phenotype of mutations in the PRRT2 gene to include the frequent occurrence of migraine and HM with PKD/IC, and the association of mutations with EA and HM and with familial HM alone. We have also extended the PRRT2 mutation type and frequency in PKD and other episodic neurologic disorders.
| S-EPMC3511930 | biostudies-literature
Project description:http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)2330-1619/homepage/mdc312518-sup-v001.htm.
| S-EPMC6174441 | biostudies-literature
Project description: Not available
| S-EPMC8370144 | biostudies-literature
Project description:ObjectiveWhole genome sequencing and the screening of 103 families recently led us to identify PRRT2 (proline-rich-transmembrane protein) as the gene causing infantile convulsions (IC) with paroxysmal kinesigenic dyskinesia (PKD) (PKD/IC syndrome, formerly ICCA). There is interfamilial and intrafamilial variability and the patients may have IC or PKD. Association of IC with hemiplegic migraine (HM) has also been reported. In order to explore the mutational and clinical spectra, we analyzed 34 additional families with either typical PKD/IC or PKD/IC with migraine.MethodsWe performed Sanger sequencing of all PRRT2 coding exons and of exon-intron boundaries in the probands and in their relatives whenever appropriate.ResultsTwo known and 2 novel PRRT2 mutations were detected in 18 families. The p.R217Pfs*8 recurrent mutation was found in ≈50% of typical PKD/IC, and the unreported p.R145Gfs*31 in one more typical family. PRRT2 mutations were also found in PKD/IC with migraine: p.R217Pfs*8 cosegregated with PKD associated with HM in one family, and was also detected in one IC patient having migraine with aura, in related PKD/IC familial patients having migraine without aura, and in one sporadic migraineur with abnormal MRI. Previously reported p.R240X was found in one patient with PKD with migraine without aura. The novel frameshift p.S248Afs*65 was identified in a PKD/IC family member with IC and migraine with aura.ConclusionsWe extend the spectrum of PRRT2 mutations and phenotypes to HM and to other types of migraine in the context of PKD/IC, and emphasize the phenotypic pleiotropy seen in patients with PRRT2 mutations.
| S-EPMC3511924 | biostudies-literature
Project description:To explore the potential causative genes of paroxysmal hypnogenic dyskinesia (PHD), which was initially considered a subtype of paroxysmal dyskinesia and has been recently considered a form of nocturnal frontal lobe epilepsy (NFLE).Eleven patients with PHD were recruited. Mutations in proline-rich region transmembrane protein-2 (PRRT2), myofibrillogenesis regulator 1 (MR-1), solute carrier family 2, member 1 (SLC2A1), calcium-activated potassium channel alpha subunit (KCNMA1), cholinergic receptor, nicotinic, alpha 4 (CHRNA4), cholinergic receptor, nicotinic, beta 2 (CHRNB2), cholinergic receptor, nicotinic, alpha 2 (CHRNA2), and potassium channel subfamily T member 1 (KCNT1) were screened by direct sequencing.Two PRRT2 mutations were identified in patients with typical PHD. A mutation of c.649dupC (p.Arg217ProfsX8) was identified in a patient with PHD and his father who was diagnosed with paroxysmal kinesigenic dyskinesia. An additional mutation of c.640G>C (p.Ala214Pro) was identified in a sporadic patient and his asymptomatic mother. No mutations were found in the other screened genes.The present study identified PRRT2 mutations in PHD, extending the phenotypic spectrum of PRRT2 and supporting the classification of PHD as a subtype of paroxysmal dyskinesia but not NFLE. Based on the results of this study, screening for the PRRT2 mutation is recommended in patients with PHD.
| S-EPMC4830198 | biostudies-other
Project description:ObjectiveTo perform a clinical and genetic study of a family with benign familial infantile seizures (BFIS) and, upon finding a PRRT2 gene mutation, to study a cohort of probands with a similar phenotype. We extended the study to all available family members to find out whether PRRT2 mutations cosegregated with additional symptoms.MethodsWe carried out a clinical and genealogic study of a 3-generation family and of 32 additional probands with BFIS (11 families), infantile convulsions and paroxysmal choreoathetosis (ICCA) (9 families), BFIS/generalized epilepsy with febrile seizures plus (5 families), and sporadic benign neonatal or infantile seizures (7 probands/families). We performed a genetic study consisting of linkage analysis and PRRT2 screening of the 33 probands/families.ResultsWe obtained a positive linkage in the 16p11.3-q23.1 chromosomal region in the large BFIS family. Mutation analysis of PRRT2 gene revealed a c.649dupC (p.Arg217Profs*8) in all affected individuals. PRRT2 analysis of the 32 additional probands showed mutations in 10, 8 familial and 2 sporadic, probands. Overall we found PRRT2 mutations in 11 probands with a mutation rate of 11 out of 33 (33%). BFIS co-occurred with migraine and febrile seizures in 2 families, with childhood absence epilepsy in one family and with hemiplegic migraine in one family.ConclusionOur results confirm the predominant role of PRRT2 mutations in BFIS and expand the spectrum of PRRT2-associated phenotypes to include febrile seizures, childhood absence seizures, migraine, and hemiplegic migraine.
| S-EPMC3511926 | biostudies-literature
Project description:Paroxysmal kinesigenic dyskinesia with infantile convulsions (PKD/IC) is an episodic movement disorder with autosomal-dominant inheritance and high penetrance, but the causative genetic mutation is unknown. We have now identified four truncating mutations involving the gene PRRT2 in the vast majority (24/25) of well-characterized families with PKD/IC. PRRT2 truncating mutations were also detected in 28 of 78 additional families. PRRT2 encodes a proline-rich transmembrane protein of unknown function that has been reported to interact with the t-SNARE, SNAP25. PRRT2 localizes to axons but not to dendritic processes in primary neuronal culture, and mutants associated with PKD/IC lead to dramatically reduced PRRT2 levels, leading ultimately to neuronal hyperexcitability that manifests in vivo as PKD/IC.
| S-EPMC3334308 | biostudies-literature
Project description:BackgroundParoxysmal kinesigenic dyskinesia (PKD) is a rare neurological disorder, characterized by attacks of involuntary movements triggered by sudden action. Variants in proline-rich transmembrane protein 2 (PRRT2) are the most common genetic cause of PKD.ObjectiveThe objective was to investigate the clinical and genetic characteristics of PKD and to establish genotype-phenotype correlations.MethodsWe enrolled 219 PKD patients, documented their clinical information and performed PRRT2 screening using Sanger sequencing. Whole exome sequencing was performed on 49 PKD probands without PRRT2 variants. Genotype-phenotype correlation analyses were conducted on the probands.ResultsAmong 219 PKD patients (99 cases from 39 families and 120 sporadic cases), 16 PRRT2 variants were identified. Nine variants (c.879+4A>G, c.879+5G>A, c.856G>A, c.955G>T, c.884G>C, c.649C>T, c.649dupC, c.649delC and c.696_697delCA) were previously known, while seven were novel (c.367_403del, c.347_348delAA, c.835C>T, c.116dupC, c.837_838insC, c.916_937del and c.902G>A). The mean interval from onset to diagnosis was 7.94 years. Compared to patients without PRRT2 variants, patients with the variants were more likely to have a positive family history, an earlier age of onset and a higher prevalence of falls during pre-treatment attacks (27.14% versus 8.99%, respectively). Patients with truncated PRRT2 variants tend to have bilateral attacks. We identified two transmembrane protein 151A (TMEM151A) variants including a novel variant (c.368G>C) and a reported variant (c.203C>T) in two PRRT2-negative probands with PKD.ConclusionThese findings provide insights on the clinical characteristics, diagnostic timeline and treatment response of PKD patients. PKD patients with truncated PRRT2 variants may tend to have more severe paroxysmal symptoms. This study expands the spectrum of PRRT2 and TMEM151A variants. Carbamazepine and oxcarbazepine are both used as a first-line treatment choice for PKD patients.
| S-EPMC10798112 | biostudies-literature
Project description:Mutations in the proline-rich transmembrane protein 2 (PRRT2) are associated with paroxysmal kinesigenic dyskinesia (PKD) and several other paroxysmal neurological diseases, but the PRRT2 function and pathogenic mechanisms remain largely obscure. Here we show that PRRT2 is a presynaptic protein that interacts with components of the SNARE complex and downregulates its formation. Loss-of-function mutant mice showed PKD-like phenotypes triggered by generalized seizures, hyperthermia, or optogenetic stimulation of the cerebellum. Mutant mice with specific PRRT2 deletion in cerebellar granule cells (GCs) recapitulate the behavioral phenotypes seen in Prrt2-null mice. Furthermore, recording made in cerebellar slices showed that optogenetic stimulation of GCs results in transient elevation followed by suppression of Purkinje cell firing. The anticonvulsant drug carbamazepine used in PKD treatment also relieved PKD-like behaviors in mutant mice. Together, our findings identify PRRT2 as a novel regulator of the SNARE complex and provide a circuit mechanism underlying the PRRT2-related behaviors.
| S-EPMC5752836 | biostudies-literature
Project description:BackgroundRecently, heterozygous mutations in PRRT2 (Chr 16p11.2) have been identified in Han Chinese, Japanese and Caucasians with paroxysmal kinesigenic dyskinesia. In previous work, a paroxysmal kinesigenic dyskinesia locus was mapped to Chr 16p11.2 - q11.2 in a multiplex African-American family.MethodsSanger sequencing was used to analyze all four PRRT2 exons for sequence variants in 13 probands (9 Caucasian, 1 Caucasian-Thai, 1 Vietnamese and 2 African-American) with some form of paroxysmal dyskinesia.ResultsOne patient of mixed Caucasian-Thai background and one African-American family harbored the previously described hotspot mutation in PRRT2 (c.649dupC, p.R217Pfs*8). Another African-American family was found to have a novel mutation (c.776dupG, p.E260*). Both of these variants are likely to cause loss-of-function via nonsense-mediated decay of mutant PRRT2 transcripts. All affected individuals had classic paroxysmal kinesigenic dyskinesia phenotypes.ConclusionsHeterozygous PRRT2 gene mutations also cause paroxysmal kinesigenic dyskinesia in African-Americans. The c.649dupC hotspot mutation in PRRT2 is common across racial groups.
| S-EPMC3460747 | biostudies-literature