High prevalence of copy number variations in the Japanese participants with suspected MODY.

Maturity-Onset Diabetes of the Young (MODY) is a diabetes mellitus subtype caused by a single gene. The detection rate of the responsible gene is 27% in the United Kingdom, indicating that the causative gene remains unknown in the majority of clinically diagnosed MODY cases. To improve the detection rate, we applied comprehensive genetic testing using whole exome sequencing (WES) followed by Multiplex Ligation-dependent Probe Amplification (MLPA) and functional analyses. Twenty-one unrelated Japanese participants with MODY were enrolled in the study. To detect copy number variations (CNVs), WES was performed first, followed by MLPA analysis for participants who were negative on the basis of WES. Undetermined variants were analyzed according to their functional properties. WES identified 7 pathogenic and 3 novel likely pathogenic variants in the 21 participants. Functional analyses revealed that 1 in 3 variants was pathogenic. MLPA analysis applied to the remaining 13 undetermined samples identified 4 cases with pathogenic CNVs: 3 in HNF4A and 1 in HNF1B. Pathogenic variants were identified in 12 participants (12/21, 57.1%) - relatively high rate reported to date. Notably, one-third of the participants had CNVs in HNF4A or HNF1B, indicating a limitation of WES-only screening.

Identification of Prostaglandin I2 Synthase Rare Variants in Patients With Williams Syndrome and Severe Peripheral Pulmonary Stenosis.

BACKGROUND: Peripheral pulmonary stenosis (PPS) is a condition characterized by the narrowing of the pulmonary arteries, which impairs blood flow to the lung. The mechanisms underlying PPS pathogenesis remain unclear. Thus, the aim of this study was to investigate the genetic background of patients with severe PPS to elucidate the pathogenesis of this condition. METHODS AND RESULTS: We performed genetic testing and functional analyses on a pediatric patient with PPS and Williams syndrome (WS), followed by genetic testing on 12 patients with WS and mild-to-severe PPS, 50 patients with WS but not PPS, and 21 patients with severe PPS but not WS. Whole-exome sequencing identified a rare PTGIS nonsense variant (p.E314X) in a patient with WS and severe PPS. Prostaglandin I2 synthase (PTGIS) expression was significantly downregulated and cell proliferation and migration rates were significantly increased in cells transfected with the PTGIS p.E314X variant-encoding construct when compared with that in cells transfected with the wild-type PTGIS-encoding construct. p.E314X reduced the tube formation ability in human pulmonary artery endothelial cells and caspase 3/7 activity in both human pulmonary artery endothelial cells and human pulmonary artery smooth muscle cells. Compared with healthy controls, patients with PPS exhibited downregulated pulmonary artery endothelial prostaglandin I2 synthase levels and urinary prostaglandin I metabolite levels. We identified another PTGIS rare splice-site variant (c.1358+2T>C) in another pediatric patient with WS and severe PPS. CONCLUSIONS: In total, 2 rare nonsense/splice-site PTGIS variants were identified in 2 pediatric patients with WS and severe PPS. PTGIS variants may be involved in PPS pathogenesis, and PTGIS represents an effective therapeutic target.

Factors associated with early-onset intracranial aneurysms in patients with autosomal dominant polycystic kidney disease.

BACKGROUND: Recently, the importance of attribute-based medicine has been emphasized. The effects of early-onset intracranial aneurysms on patients can be significant and long-lasting. Herein, we compared the factors associated with intracranial aneurysms in patients with autosomal dominant polycystic kidney disease (ADPKD) according to age categories (≥ 50 years, < 50 years). METHODS: We included 519 ADPKD patients, with a median age of 44 years, estimated glomerular filtration rate of 54.5 mL/min/1.73 m2, and total follow-up duration of 3104 patient-years. Logistic regression analyses were performed to determine factors associated with intracranial aneurysms. RESULTS: Regarding the presence of intracranial aneurysm, significant interactions were identified between the age category (age ≥ 50 years), female sex (P = 0.0027 for the interaction) and hypertension (P = 0.0074 for the interaction). Female sex and hypertension were associated with intracranial aneurysm risk factors only in patients aged ≥ 50 years. The presence of intracranial aneurysm was significantly associated with chronic kidney disease (CKD) stages 4-5 (odds ratio [OR] = 3.87, P = 0.0007) and family history of intracranial aneurysm or subarachnoid hemorrhage (OR = 2.30, P = 0.0217) in patients aged < 50 years. For patients aged ≥ 50 years, in addition to the abovementioned factors [OR = 2.38, P = 0.0355 for CKD stages 4-5; OR = 3.49, P = 0.0094 for family history of intracranial aneurysm or subarachnoid hemorrhage], female sex (OR = 4.51, P = 0.0005), and hypertension (OR = 5.89, P = 0.0012) were also associated with intracranial aneurysm. CONCLUSION: Kidney dysfunction and family history of intracranial aneurysm or subarachnoid hemorrhage are risk factors for early-onset intracranial aneurysm. Patients aged < 50 years with a family history of intracranial aneurysm or subarachnoid hemorrhage or with CKD stages 4-5 may be at an increased risk of early-onset intracranial aneurysm.

The c.1617del variant of TMEM260 is identified as the most frequent single gene determinant for Japanese patients with a specific type of congenital heart disease.

Although the molecular mechanisms underlying congenital heart disease (CHD) remain poorly understood, recent advances in genetic analysis have facilitated the exploration of causative genes for CHD. We reported that the pathogenic variant c.1617del of TMEM260, which encodes a transmembrane protein, is highly associated with CHD, specifically persistent truncus arteriosus (PTA), the most severe cardiac outflow tract (OFT) defect. Using whole-exome sequencing, the c.1617del variant was identified in two siblings with PTA in a Japanese family and in three of the 26 DNAs obtained from Japanese individuals with PTA. The c.1617del of TMEM260 has been found only in East Asians, especially Japanese and Korean populations, and the frequency of this variant in PTA is estimated to be next to that of the 22q11.2 deletion, the most well-known genetic cause of PTA. Phenotype of patients with c.1617del appears to be predominantly in the heart, although TMEM260 is responsible for structural heart defects and renal anomalies syndrome (SHDRA). The mouse TMEM260 variant (p.W535Cfs*56), synonymous with the human variant (p.W539Cfs*9), exhibited truncation and downregulation by western blotting, and aggregation by immunocytochemistry. In situ hybridization demonstrated that Tmem260 is expressed ubiquitously during embryogenesis, including in the development of cardiac OFT implicated in PTA. This expression may be regulated by a ~ 0.8 kb genomic region in intron 3 of Tmem260 that includes multiple highly conserved binding sites for essential cardiac transcription factors, thus revealing that the c.1617del variant of TMEM260 is the major single-gene variant responsible for PTA in the Japanese population.

Functional characterization of variants found in Japanese patients with hereditary hemorrhagic telangiectasia.

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant form of vascular dysplasia. Genetic diagnosis is made by identifying loss-of-function variants in genes, such as ENG and ACVRL1. However, the causal mechanisms of various variants of unknown significance remains unclear. In this study, we analyzed 12 Japanese patients from 11 families who were clinically diagnosed with HHT. Sequencing analysis identified 11 distinct variants in ACVRL1 and ENG. Three of the 11 were truncating variants, leading to a definitive diagnosis, whereas the remaining eight were splice-site and missense variants that required functional analyses. In silico splicing analyses demonstrated that three variants, c.526-3C > G and c.598C > G in ACVRL1, and c.690-1G > A in ENG, caused aberrant splicing, as confirmed by a minigene assay. The five remaining missense variants were p.Arg67Gln, p.Ile256Asn, p.Leu285Pro, and p.Pro424Leu in ACVRL and p.Pro165His in ENG. Nanoluciferase-based bioluminescence analyses demonstrated that these ACVRL1 variants impaired cell membrane trafficking, resulting in the loss of bone morphogenetic protein 9 (BMP9) signal transduction. In contrast, the ENG mutation impaired BMP9 signaling despite normal cell membrane expression. The updated functional analysis methods performed in this study will facilitate effective genetic testing and appropriate medical care for patients with HHT.

Synergistic Interaction of Thyroid Autoantibodies and Ring Finger Protein 213 Variant in Moyamoya Disease.

Recently, thyroid autoantibodies were found to be associated with moyamoya disease (MMD). The ring finger protein 213 (RNF213) p.R4810K variant represents the most important susceptibility genotype of this disease, but its relationship with thyroid autoantibodies remains to be elucidated. Thus, in this study, we aimed to evaluate the clinical relevance of thyroid autoantibodies in each RNF213 genotype in patients with MMD. Included in this study were patients with MMD without a thyroid disease history and in euthyroid status; they were then classified into the mutated or nonmutated based on the RNF213 p.R4810K genotype and positive or negative based on thyroid autoantibody (thyroperoxidase and thyroglobulin) levels. Clinical data of each group were thereafter evaluated. Among the 209 patients, the mutated RNF213 p.R4810K variant and positive thyroid autoantibodies were detected in 155 and 41 patients, respectively. Positive thyroid autoantibodies were found to be more common in the nonmutated patients than in the mutated patients (31.5% vs. 15.5%; P = 0.011). In the mutated patients, as compared to autoantibody-negative patients, autoantibody-positive patients were determined to be more likely to have advanced disease with posterior cerebral artery involvement (54.2% vs. 29.0%; P = 0.017), white matter infarction (58.3% vs. 37.6%; P = 0.046), and a higher modified Rankin Scale at last visit (16.7% vs. 3.1%; P = 0.021). These results suggest that thyroid autoantibodies can act as an immunity inducer in patients with MMD lacking the susceptibility gene RNF213 p.R4810K variant. Moreover, the simultaneous presence of thyroid autoantibodies and the variant seems to aggravate the disease, which indicates synergy between thyroid autoantibodies and the variant.

Difference in Clinical Phenotype, Mutation Position, and Structural Change of RNF213 Rare Variants Between Pediatric and Adult Japanese Patients with Moyamoya Disease.

It is unclear how rare RNF213 variants, other than the p.R4810K founder variant, affect the clinical phenotype or the function of RNF213 in moyamoya disease (MMD). This study included 151 Japanese patients with MMD. After performing targeted resequencing for all coding exons in RNF213, we investigated the clinical phenotype and statistically analyzed the genotype-phenotype correlation. We mapped RNF213 variants on a three-dimensional (3D) model of human RNF213 and analyzed the structural changes due to variants. The RNF213 p.R4810K homozygous variant, p.R4810K heterozygous variant, and wild type were detected in 10 (6.6%), 111 (73.5%), and 30 (19.9%) MMD patients, respectively. In addition, 15 rare variants were detected in 16 (10.6%) patients. In addition to the influence of the p.R4810K homozygous variant, the frequency of cerebral infarction at disease onset was higher in pediatric patients with other rare variants (3/6, 50.0%, P = 0.006) than in those with only the p.R4810K heterozygous variant or with no variants (2/51, 3.9%). Furthermore, on 3D modelling of RNF213, the majority of rare variants found in pediatric patients were located in the E3 module and associated with salt bridge loss, contrary to the results for adult patients. The clinical phenotype of rare RNF213 variants, mapped mutation position, and their predicted structural change differed between pediatric and adult patients with MMD. Rare RNF213 variants, in addition to the founder p.R4810K homozygous variant, can influence MMD clinical phenotypes or structural change which may contribute to the destabilization of RNF213.

A novel pathogenic variant in the glucokinase gene found in two Japanese siblings with maturity-onset diabetes of the young 2.

Glucokinase is a glycolytic enzyme that catalyzes the phosphorylation of glucose to glucose-6-phospate in the first step of the glycolytic pathway. It also regulates the threshold for insulin secretion from pancreatic beta cells by catalyzing the phosphorylation of glucose and plays an important role as a glucose sensor. Pathogenic variants in the glucokinase gene (GCK) cause non-progressive but persistent mild fasting hyperglycemia, also recognized as maturity-onset diabetes of the young 2 (MODY2). This report presents the case of two Japanese siblings with MODY2, who were initially diagnosed with impaired glucose intolerance at 20 and 17 years of age, and later developed diabetes mellitus. They had no history of obesity, were negative for islet-related autoantibodies and their serum C-peptide level were within the normal range. Diabetic complications were not observed. Next-generation sequencing revealed a novel heterozygous variant in GCK (NM_000162.5: c.1088A>G, p.Asp363Gly) in both siblings. This variant has not been reported previously. In silico functional analyses, using SIFT and MutationTaster, suggested that the variant was damaging. To confirm the functional impact of the mutated GCK, the HiBiT-tagged p.Asp363Gly variant and the wild-type GCK were transiently expressed in HEK293T cells. The cells expressing the variant GCK exhibited 79% less bioluminescence, compared to those expressing the wild-type GCK, suggesting that the pathophysiology of the variant was a result of haploinsufficiency.

Variant spectrum of PIEZO1 and KCNN4 in Japanese patients with dehydrated hereditary stomatocytosis.

Hereditary stomatocytosis (HSt) is a type of congenital hemolytic anemia caused by abnormally increased cation permeability of erythrocyte membranes. Dehydrated HSt (DHSt) is the most common subtype of HSt and is diagnosed based on clinical and laboratory findings related to erythrocytes. PIEZO1 and KCNN4 have been recognized as causative genes, and many related variants have been reported. We analyzed the genomic background of 23 patients from 20 Japanese families suspected of having DHSt using a target capture sequence and identified pathogenic/likely pathogenic variants of PIEZO1 or KCNN4 in 12 families.

Loss-of-function mutations in SGCE found in Japanese patients with myoclonus-dystonia.

SGCE myoclonus-dystonia is a monogenic form of dystonia with an autosomal dominant mode of inheritance that co-occurs with a myoclonic jerk. In this study, we present 12 Japanese patients from nine families with this disease. Targeted next-generation sequencing covering major causative genes for monogenic dystonias identified nine distinct SGCE mutations from each of the families: three nonsense, two frameshift, two missense, one in-frame 15 bp deletion, and one splice donor site mutations, of which four were previously unreported. One missense mutation (c.662G>T, p.Gly221Val) was located at the 3' end of exon 5 (NM_001099400), which was predicted to cause aberrant splicing according to in silico predictions. Minigene assays performed together with the c.825+1G>C mutation demonstrated complete skipping of exon 5 and 6, respectively, in their transcripts. The other missense (c.1345A>G, p.Met449Val) and 15 bp deletion (c.168_182del, p.Phe58_Leu62del) mutations showed a significant reduction in cell membrane expression via HiBiT bioluminescence assay. Therefore, we concluded that all the detected mutations were disease-causing. Unlike the other detected mutations, p.Met449Val affects only isoform 3 (NP_001092870 encoded by NM_001099400) among the variously known isoforms of SGCE. This isoform is brain-specific and is mostly expressed in the cerebellum, which supports recent studies showing that cerebellar dysfunction is a key element in the pathophysiology of SGCE myoclonus-dystonia.

Impact of kidney function and kidney volume on intracranial aneurysms in patients with autosomal dominant polycystic kidney disease.

Presently, only personal or family history of intracranial aneurysm/subarachnoid hemorrhage (IA/SAH) has been established as a risk factor for IA in autosomal dominant polycystic kidney disease (ADPKD). This study aimed to verify the association between kidney function/volume and IAs in patients with ADPKD. This study included 519 patients with ADPKD. At baseline IA screening, the median age and estimated glomerular filtration rate were 44 years and 54.5 mL/min/1.73 m2, respectively. Family IA/SAH history was confirmed in 18.1% of the patients, and 54.3% of the patients had hypertension. The IA point prevalence was 12.5%. During clinical follow up of 3104 patient-years, de novo IA was detected in 29 patients (0.93% patient-years). The IA period prevalence was 18.1% (median age, 60 years). Multivariable logistic regression demonstrated that total kidney volume (TKV) ≥ 1000 mL (odds ratio [OR] = 2.81), height-adjusted TKV ≥ 500 mL (OR = 2.81), Mayo imaging classification Class 1D-1E (OR = 2.52), and chronic kidney disease stages 3-5 (OR = 2.31) were significantly associated with IA formation. IAs in patients with ADPKD may be associated not only with general risk factors for IAs but also with declining kidney function and increased KV. Kidney disease progression may contribute to effective IA screening and treatment planning in patients with ADPKD.

Whole-exome sequencing in a Japanese multiplex family identifies new susceptibility genes for intracranial aneurysms.

BACKGROUND: Intracranial aneurysms (IAs) cause subarachnoid hemorrhage, which has high rates of mortality and morbidity when ruptured. Recently, the role of rare variants in the genetic background of complex diseases has been increasingly recognized. The aim of this study was to identify rare variants for susceptibility to IA. METHODS: Whole-exome sequencing was performed on seven members of a Japanese pedigree with highly aggregated IA. Candidate genes harboring co-segregating rare variants with IA were re-sequenced and tested for association with IA using additional 500 probands and 323 non-IA controls. Functional analysis of rare variants detected in the pedigree was also conducted. RESULTS: We identified two gene variants shared among all four affected participants in the pedigree. One was the splicing donor c.1515+1G>A variant in NPNT (Nephronectin), which was confirmed to cause aberrant splicing by a minigene assay. The other was the missense p.P83T variant in CBY2 (Chibby family member 2). Overexpression of p.P83T CBY2 fused with red fluorescent protein tended to aggregate in the cytoplasm. Although Nephronectin has been previously reported to be involved in endothelial angiogenic functions, CBY2 is a novel molecule in terms of vascular pathophysiology. We confirmed that CBY2 was expressed in cerebrovascular smooth muscle cells in an isoform2-specific manner. Targeted CBY2 re-sequencing in additional case-control samples identified three deleterious rare variants (p.R46H, p.P83T, and p.L183R) in seven probands, showing a significant enrichment in the overall probands (8/501) compared to the controls (0/323) (p = 0.026, Fisher's extract test). CONCLUSIONS: NPNT and CBY2 were identified as novel susceptibility genes for IA. The highly heterogeneous and polygenic architecture of IA susceptibility can be uncovered by accumulating extensive analyses that focus on each pedigree with a high incidence of IA.

Triple bypass for multisystem smooth muscle dysfunction syndrome due to Arg179His ACTA2 mutation.

Missense mutations in the smooth muscle-specific isoform of the alpha-actin (ACTA2) gene, which encodes smooth muscle actin, congenitally cause systemic smooth muscle dysfunction, leading to multiple systemic smooth muscle dysfunction syndrome. This disease is often diagnosed through the development of congenital mydriasis, patent ductus arteriosus, or thoracic aortic aneurysm at a young age. Some patients develop cerebrovascular lesions, also known as ACTA2 cerebral arteriopathy, which cause ischemic stroke and require surgical revascularization. However, an effective and safe treatment has not yet been established owing to the rarity of the disease. Furthermore, most reports of this disease involve children, with only a few reports on adults and few detailed reports on treatment outcomes published to date. We report a 46-year-old woman with ACTA2 cerebral arteriopathy caused by Arg179His, the most common mutation in this disease; she is the oldest patient reported with this disease to the best of our knowledge. The patient was diagnosed with multiple systemic smooth muscle dysfunction syndrome and ACTA2 cerebral arteriopathy after experiencing a stroke in the right cingulate gyrus. She underwent direct triple bypass with three anastomoses of the right superficial temporal artery to the middle and anterior cerebral arteries. She developed an ischemic stroke as a postoperative complication.The efficacy and safety of this procedure have not been clearly confirmed owing to the frailty of the donor superficial temporal artery and the poor development of collateral circulation; however, direct bypass should be considered a treatment option for patients experiencing progressive multiple strokes.

Dystonic Tremor in Adult-onset DYT-KMT2B.

KMT2B-related dystonia (DYT28, DYT-KMT2B) is an inherited dystonia that generally begins in the lower limbs during childhood and evolves into generalized dystonia. We herein report a case of adult-onset DYT28 with dystonic tremor. A 27-year-old woman initially displayed right upper limb and cervical tremors over the course of 1 year. A neurological examination also revealed cervical and lower limb dystonia. Although the disease generally develops during childhood, we diagnosed the woman with DYT28, as genetic testing revealed a mutation in KMT2B. Adult-onset patients with DYT28 might also show uncommon symptoms as well as DYT-TOR1A (DYT1).

A Cardiac Arrest Case due to Left Coronary Artery Compression in Congenital Heart Disease-Associated Pulmonary Arterial Hypertension.

We report the case of an adult who had a cardiac arrest in the setting of pulmonary hypertension and a previously repaired intermediate atrioventricular septal defect, with left main coronary trunk stenosis due to dilatation of the main pulmonary artery. In patients with pulmonary hypertension exhibiting anginal symptoms, it is advisable to perform chest contrast computed tomography to confirm the pulmonary artery diameter and the presence of coronary artery compression. In addition, our case highlights the importance of early collaboration among specialists during the transition from adolescence to adulthood.

Nous décrivons le cas d'un adulte ayant subi un arrêt cardiaque alors qu'il présentait une hypertension pulmonaire et qu'il avait déjà subi la réparation d'une communication septale auriculoventriculaire intermédiaire, avec sténose de l'artère coronaire gauche principale causée par la dilatation de l'artère pulmonaire principale. Chez les patients atteints d'hypertension pulmonaire qui présentent des symptômes angineux, il est recommandé d'effectuer une tomodensitométrie thoracique avec produit de contraste pour confirmer le diamètre de l'artère pulmonaire et la présence d'une compression de l'artère coronaire. Notre cas souligne également l'importance d'établir sans tarder une collaboration entre spécialistes lors de la transition entre l'adolescence et l'âge adulte.

Absence of the RNF213 p.R4810K variant may indicate a severe form of pediatric moyamoya disease in Japanese patients.

OBJECTIVE: The authors' objective was to investigate the influence of the RNF213 p.R4810K variant on the clinical presentation and outcomes of Japanese pediatric patients with moyamoya disease. METHODS: A total of 129 Japanese patients with pediatric-onset moyamoya disease (onset age ≤ 15 years) who visited the authors' department from 2012 to 2020 participated in this study. After RNF213 p.R4810K genotyping of each patient was performed, the relationship between genotype and clinical presentation or outcomes, including onset age, initial presentation, surgical outcomes, and subsequent cerebrovascular events, was evaluated. Patients without the p.R4810K variant were tested for RNF213 variants other than p.R4810K. The authors especially focused on the results of patients who presented with moyamoya disease at younger than 1 year of age (infantile onset). RESULTS: Compared with the patients with heterozygous variants, patients without the p.R4810K variant were younger at onset (7.1 ± 3.7 vs 4.4 ± 0.9 years), and all 4 patients with infantile onset lacked the p.R4810K variant. A greater proportion of patients without the p.R4810K variant presented with infarction than patients with the heterozygous variant (24.0% vs 7.6%) and a decreased proportion presented with transient ischemic attack (36.0% vs 71.7%). No significant correlation was observed between p.R4810K genotype and clinical outcomes, including surgical outcomes and subsequent cerebrovascular events; however, a decreased proportion of patients without the p.R4810K variant had good surgical outcomes compared with that of patients with the heterozygous variant (76.5% vs 92.2%). Among the 25 patients without the p.R4810K variant, 8 rare variants other than p.R4810K were identified. Three of 4 patients with infantile onset had RNF213 variants other than p.R4810K, which had a more severe functional effect on this gene than p.R4810K. CONCLUSIONS: Absence of the RNF213 p.R4810K variant may be a novel biomarker for identification of a severe form of pediatric moyamoya disease.

Case Report: Long-Term Suppression of Paroxysmal Kinesigenic Dyskinesia After Bilateral Thalamotomy.

Background: Paroxysmal kinesigenic dyskinesia (PKD) is a movement disorder characterized by transient dyskinetic movements, including dystonia, chorea, or both, triggered by sudden voluntary movements. Carbamazepine and other antiepileptic drugs (AEDs) are widely used in the treatment of PKD, and they provide complete remission in 80-90% of medically treated patients. However, the adverse effects of AEDs include drowsiness and dizziness, which interfere with patients' daily lives. For those with poor compatibility with AEDs, other treatment approaches are warranted. Case Report: A 19-year-old man presented to our institute with right hand and foot dyskinesia. He had a significant family history of PKD; his uncle, grandfather, and grandfather's brother had PKD. The patient first experienced paroxysmal involuntary left hand and toe flexion with left forearm pronation triggered by sudden voluntary movements at the age of 14. Carbamazepine (100 mg/day) was prescribed, which led to a significant reduction in the frequency of attacks. However, carbamazepine induced drowsiness, which significantly interfered with his daily life, especially school life. He underwent right-sided ventro-oral (Vo) thalamotomy at the age of 15, which resulted in complete resolution of PKD attacks immediately after the surgery. Four months after the thalamotomy, he developed right elbow, hand, and toe flexion. He underwent left-sided Vo thalamotomy at the age of 19. Immediately after the surgery, the PKD attacks resolved completely. However, mild dysarthria developed, which spontaneously resolved within three months. Left-sided PKD attacks never developed six years after the right Vo thalamotomy, and right-sided PKD attacks never developed two years after the left Vo thalamotomy without medication. Conclusion: The present case showed long-term suppression of bilateral PKDs after bilateral thalamotomy, which led to drug-free conditions.

Deep intronic deletion in intron 3 of PLP1 is associated with a severe phenotype of Pelizaeus-Merzbacher disease.

Recently, altered PLP1 splicing was confirmed as a genetic cause of hypomyelination of early myelinating structures (HEMS). A novel deep intronic deletion in intron 3 of PLP1 (NM_000533.5: c.453+59_+259del) was identified, and an in vitro minigene assay detected abnormal splicing patterns. However, the clinical and radiological findings of the patient were compatible with a severe phenotype of Pelizaeus-Merzbacher disease rather than HEMS, which may be due to undetected abnormal PLP1 splicing.