Hexanucleotide repeat expansion in SCA36 reduces the expression of genes involved in ribosome biosynthesis and protein translation.

Hereditary spinocerebellar ataxia (SCA) is a group of clinically and genetically heterogeneous inherited disorders characterized by slowly progressive cerebellar ataxia. We ascertained a Japanese pedigree with autosomal dominant SCA comprising four family members, including two patients. We identified a GGCCTG repeat expansion of intron 1 in the NOP56 gene by Southern blotting, resulting in a molecular diagnosis of SCA36. RNA sequencing using peripheral blood revealed that the expression of genes involved in ribosomal organization and translation was decreased in patients carrying the GGCCTG repeat expansion. Genes involved in pathways associated with ribosomal organization and translation were enriched and differentially expressed in the patients. We propose a novel hypothesis that the GGCCTG repeat expansion contributes to the pathogenesis of SCA36 by causing a global disruption of translation resulting from ribosomal dysfunction.

Episodic ataxia type 2 with a novel missense variant (Leu602Arg) in CACNA1A.

Autosomal dominant episodic ataxia type 2 (EA2) is caused by variants in CACNA1A. We examined a 20-year-old male with EA symptoms from a Japanese family with hereditary EA. Cerebellar atrophy was not evident, but single photon emission computed tomography showed cerebellar hypoperfusion. We identified a novel nonsynonymous variant in CACNA1A, NM_001127222.2:c.1805T>G (p.Leu602Arg), which is predicted to be functionally deleterious; therefore, this variant is likely responsible for EA2 in this pedigree.

Duodenal microbiome in chronic kidney disease.

BACKGROUND: The intestinal microbiome is involved in the pathogenesis of chronic kidney disease (CKD). Despite its importance, the microbiome of the small intestinal mucosa has been little studied due to sampling difficulties, and previous studies have mainly focused on fecal sources for microbiome studies. We aimed to characterize the small intestinal microbiome of CKD patients by studying the microbiome collected from duodenal and fecal samples of CKD patients and healthy controls. METHODS: Overall, 28 stage 5 CKD patients and 21 healthy participants were enrolled. Mucosal samples were collected from the deep duodenum during esophagogastroduodenoscopy and fecal samples were also collected. The 16S ribosomal RNA gene sequencing using Qiime2 was used to investigate and compare the microbial structure and metagenomic function of the duodenal and fecal microbiomes. RESULTS: The duodenal flora of CKD patients had decreased alpha diversity compared with the control group. On the basis of taxonomic composition, Veillonella and Prevotella were significantly reduced in the duodenal flora of CKD patients. The tyrosine and tryptophan metabolic pathways were enhanced in the urea toxin-related metabolic pathways based on the Kyoto Encyclopedia of Genes and Genomes database. CONCLUSION: The small intestinal microbiome in CKD patients is significantly altered, indicating that increased intestinal permeability and production of uremic toxin may occur in the upper small intestine of CKD patients.

Preoperative PI-RADS v2.1 Scoring System Improves Risk Classification in Patients Undergoing Radical Prostatectomy.

BACKGROUND/AIM: The purpose of this study was to examine the prognostic value of Prostate imaging-reporting and data system (PI-RADS) v2.1 scoring system in patients who underwent radical prostatectomy (RP). PATIENTS AND METHODS: Clinical data of 294 patients who received RP between 2006 and 2018 were reviewed and multiple parameters including PI-RADS v2.1 score were employed to identify predictive factors for biochemical recurrence (BCR). Tumor volume was calculated from prostatectomy specimens. RESULTS: Median age at operation and initial PSA level were 67 years old and 7.68 ng/ml, respectively. 44.9 and 24.8% of patients were diagnosed with PI-RADS score 4 and 5 prior to biopsies, respectively. BCR was observed in 17% of patients and median observation period was 63.43 months. After multivariate analysis, PI-RADS v2.1 score 5 [hazard ratio (HR)=2.24, p=0.0124] was an independent predictive factor of BCR in addition to clinical T stage (≥2c) (HR=2.32, p=0.0093) and biopsy Gleason score (≥8) (HR=2.81, p=0.0007). Furthermore, PI-RADS score 5 significantly stratified the prognosis in D'Amico intermediate- and high-risk groups (p=0.0174 and p=0.0013, respectively). We established novel risk classifications including PI-RADS v2.1 score and found that prognostic capabilities were improved as compared to the D'Amico classification. CONCLUSION: The PI-RADS v2.1 score exhibited significant prognostic value in patients with localized prostate cancer following RP. Risk classifications based on PI-RADS v2.1 score might provide better ability for predicting oncological outcomes as compared to the D'Amico classification system.

Clinical utility of the prognostic nutritional index in patients with metastatic hormone-sensitive prostate cancer: A retrospective, multicenter, cohort study.

BACKGROUND: The prognostic nutritional index (PNI) based on the serum albumin level and the lymphocyte count has been investigated as a prognostic factor in patients with malignant tumors. However, it has been poorly studied in prostate cancer (PCa), and little is known about its clinical utility. METHODS: Clinical data of 353 patients with de novo, metastatic, hormone-sensitive PCa (mHSPC) who received androgen deprivation therapy (ADT) were obtained from multiple institutions between 2000 and 2019. The impacts of the pretreatment PNI level on treatment response and survival, together with clinical parameters, were examined. The Mann-Whitney U test, Cox proportional hazards models, and Kaplan-Meier methods were used to evaluate significance. RESULTS: The median age and initial prostate-specific antigen level were 73 and 266.18 ng/mL, respectively. Patients with a low PNI had shorter progression-free survival (PFS), cancer-specific survival (CSS), and overall survival (OS) (p < 0.0001). On multivariate analysis, low PNI was an independent prognostic factor for OS (p = 0.0027, HR = 1.65), as well as advanced age (p = 0.049, HR = 1.38), the International Society of Urological Pathology (ISUP) grade group (GG) 5 (p = 0.0027, HR = 1.69), and elevated lactate dehydrogenase (LDH) (p < 0.0001, HR = 2.08). A propensity score-matching analysis showed that the PNI level remained a significant prognostic biomarker for PFS (p = 0.0263), CSS (p = 0.0006), and OS (p = 0.0015). Furthermore, a novel risk classification using PNI, LDH, and the ISUP GG was established to stratify patients' prognosis. An increase in the number of risk factors was significantly correlated with poor outcomes. CONCLUSIONS: A low pretreatment PNI might be an effective biomarker of poor treatment response and survival in patients with mHSPC undergoing ADT.

A Comparative Study of Tumor-Specificity and Neurotoxicity between 3-Styrylchromones and Anti-Cancer Drugs.

Background. Many anti-cancer drugs used in clinical practice cause adverse events such as oral mucositis, neurotoxicity, and extravascular leakage. We have reported that two 3-styrylchromone derivatives, 7-methoxy-3-[(1E)-2-phenylethenyl]-4H-1-benzopyran-4-one (Compound A) and 3-[(1E)-2-(4-hydroxyphenyl)ethenyl]-7-methoxy-4H-1-benzopyran-4-one (Compound B), showed the highest tumor-specificity against human oral squamous cell carcinoma (OSCC) cell lines among 291 related compounds. After confirming their superiority by comparing their tumor specificity with newly synthesized 65 derivatives, we investigated the neurotoxicity of these compounds in comparison with four popular anti-cancer drugs. Methods: Tumor-specificity (TSM, TSE, TSN) was evaluated as the ratio of mean CC50 for human normal oral mesenchymal (gingival fibroblast, pulp cell), oral epithelial cells (gingival epithelial progenitor), and neuronal cells (PC-12, SH-SY5Y, LY-PPB6, differentiated PC-12) to OSCC cells (Ca9-22, HSC-2), respectively. Results: Compounds A and B showed one order of magnitude higher TSM than newly synthesized derivatives, confirming its prominent tumor-specificity. Docetaxel showed one order of magnitude higher TSM, but two orders of magnitude lower TSE than Compounds A and B. Compounds A and B showed higher TSM, TSE, and TSN values than doxorubicin, 5-FU, and cisplatin, damaging OSCC cells at concentrations that do not affect the viability of normal epithelial and neuronal cells. QSAR prediction based on the Tox21 database suggested that Compounds A and B may inhibit the signaling pathway of estrogen-related receptors.

Case report: Frontotemporal dementia and amyotrophic lateral sclerosis caused by a missense variant (p.Arg89Trp) in the valosin-containing protein gene.

Frontotemporal dementia and/or amyotrophic lateral sclerosis 6, also known as amyotrophic lateral sclerosis 14, is an autosomal dominant, progressive neurodegenerative disorder caused by various mutations in the valosin-containing protein gene. In this report, we examined a 51-year-old female Japanese patient with frontotemporal dementia and amyotrophic lateral sclerosis. The patient began noticing gait disturbances at the age of 45 years. Neurological examination at the age of 46 years met the Awaji criteria for clinically probable amyotrophic lateral sclerosis. At the age of 49 years, she tended to have poor mood and an aversion to activity. Her symptoms gradually worsened. She required a wheelchair for transport and had difficulty communicating with others because of poor comprehension. She then began to frequently exhibit irritability. Eventually, she was admitted to the psychiatric hospital because uncontrollable violent behavior throughout the day. Longitudinal brain magnetic resonance imaging revealed progressive brain atrophy with temporal dominance, non-progressive cerebellar atrophy, and some non-specific white matter intensities. Brain single photon emission computed tomography showed hypoperfusion in the bilateral temporal lobes and cerebellar hemispheres. Clinical exome sequencing revealed the presence of a heterozygous nonsynonymous variant (NM_007126.5, c.265C>T; p.Arg89Trp) in the valosin-containing protein gene, which was absent in the 1000 Genomes Project, the Exome Aggregation Consortium Database, and the Genome Aggregation Database, and was predicted to be "damaging" by PolyPhen-2 and "deleterious" using SIFT with a Combined Annotation Dependent Depletion score of 35. We also confirmed the absence of this variant in 505 Japanese control subjects. Therefore, we concluded that the variant in the valosin-containing protein gene was responsible for the symptoms of this patient.

Oleic Acid-Containing Phosphatidylinositol Is a Blood Biomarker Candidate for SPG28.

Hereditary spastic paraplegia is a genetic neurological disorder characterized by spasticity of the lower limbs, and spastic paraplegia type 28 is one of its subtypes. Spastic paraplegia type 28 is a hereditary neurogenerative disorder with an autosomal recessive inheritance caused by loss of function of DDHD1. DDHD1 encodes phospholipase A1, which catalyzes phospholipids to lysophospholipids such as phosphatidic acids and phosphatidylinositols to lysophosphatidic acids and lysophoshatidylinositols. Quantitative changes in these phospholipids can be key to the pathogenesis of SPG28, even at subclinical levels. By lipidome analysis using plasma from mice, we globally examined phospholipids to identify molecules showing significant quantitative changes in Ddhd1 knockout mice. We then examined reproducibility of the quantitative changes in human sera including SPG28 patients. We identified nine kinds of phosphatidylinositols that show significant increases in Ddhd1 knockout mice. Of these, four kinds of phosphatidylinositols replicated the highest level in the SPG28 patient serum. All four kinds of phosphatidylinositols contained oleic acid. This observation suggests that the amount of oleic acid-containing PI was affected by loss of function of DDHD1. Our results also propose the possibility of using oleic acid-containing PI as a blood biomarker for SPG28.

Results of lifestyle modification promotion and reproductive/general health check for male partners of couples seeking conception.

Purpose: Male infertility is partially caused by an inappropriate lifestyle and comorbidities. In this study, we analyzed the prevalence of these factors and the effects of lifestyle modifications as part of male preconception care. Methods: Four hundred and two male partners of couples seeking conception with abnormal parameters upon the first semen analysis were enrolled. They were advised to modify their inappropriate lifestyle as male preconception care. Afterward, their general and male reproductive health was examined. Semen quality was compared before and after the promotion. Results: Smoking, chronic alcohol use, and genital heat stress were found in 22.6%, 47.0%, and 75.1% of patients, respectively. Palpable varicoceles, hypogonadism, obesity (body mass index ≧30 kg/m2), hypertension, zinc deficiency, hyperlipidemia, liver dysfunction, and diabetes mellitus were found in 25.9%, 17.0%, 7.0%, 14.9%, 16.2%, 37.0%, 26.9% and 3.4% of the participants, respectively; 98.8% of the patients had at least one factor. After the promotion, semen parameters and sperm DNA fragmentation were improved significantly. Improvement was found in those with palpable varicocele or hypogonadism but not in those with night work shift, abstinence (>3 days), erectile dysfunction, hypertension, obesity, zinc deficiency, or diabetes mellitus. Conclusions: Comorbidities and inappropriate lifestyle choices were common among men with infertility. The promotion of lifestyle modifications as part of male preconception care could improve semen quality without urologic intervention.

Hereditary Congenital Methemoglobinemia Diagnosed at the Age of 79 Years: A Case Report.

Background: Cardiopulmonary disorders are the most common cause of central cyanosis, and methemoglobinemia is often overlooked in the differential diagnosis of patients with central cyanosis. In most cases, methemoglobinemia is acquired and hereditary congenital methemoglobinemia is rare. Only a few case reports of congenital methemoglobinemia can be found in PubMed. To date, only four cases of congenital methemoglobinemia diagnosed after the age of 50 years have been reported. Case Presentation: A 79-year-old Japanese woman presented at our hospital with the chief complaints of dyspnea and cyanosis. She exhibited cyanosis of the lips and extremities, and her SpO2 was 80%, with oxygen administration at 5 L/min. Blood gas analysis revealed a PaO2 of 325.4 mmHg and methemoglobin level of 36.9%. The SpO2 and PaO2 values were dissociated, and methemoglobin levels were markedly elevated. Genetic analysis revealed a nonsynonymous variant in the gene encoding nicotinamide adenine dinucleotide cytochrome (NADH) B5 reductase 3 (CYB5R3), and the patient was diagnosed with congenital methemoglobinemia. Conclusions: It is important to consider methemoglobinemia in the differential diagnosis of patients with central cyanosis. At 79 years of age, our patient represents the oldest patient with this diagnosis. This report indicates that it is crucial to consider the possibility of methemoglobinemia regardless of the patient's age.

A Japanese family with dystonia due to a pathogenic variant in SGCE.

Dystonia (DYT) is a heterogeneous neurological disorder, and there are many types of DYT depending on the responsible genes. DYT11 is an autosomal dominant DYT caused by functional variants in the SGCE gene. We examined a Japanese patient with myoclonic dystonia. By using exome analysis, we identified a rare variant in the SGCE gene, NM_003919.3: c.304C > T [Arg102*], in this patient. Therefore, this patient has been molecularly diagnosed with DYT11. By Sanger sequencing, we confirmed that this variant was paternally inherited in this patient. By allele-specific PCR, we confirmed that the maternally inherited normal allele of SGCE was silenced, and only the paternally inherited variant allele was expressed in this patient. Despite the pathogenicity, identical variants have been recurrently reported in eight independent families from different ethnicities, suggesting recurrent mutations at this mutational hotspot in SGCE.

One-year clinical efficacy and safety of indigo naturalis for active ulcerative colitis: a real-world prospective study.

BACKGROUND/AIMS: Recent studies suggested a favorable effect of indigo naturalis (IN) in inducing remission for refractory ulcerative colitis (UC), however, the maintenance effect of IN for patients with UC remains unknown. Therefore, we conducted a prospective uncontrolled open-label study to analyze the efficacy and safety of IN for patients with UC. METHODS: Patients with moderate to severe active UC (clinical activity index [CAI] ≥ 8) took 2 g/day of IN for 52 weeks. CAI at weeks 0, 4, 8, and 52 and Mayo endoscopic subscore (MES) and Geboes score (GS) at weeks 0, 4, and 52 were assessed. Clinical remission (CAI ≤ 4), mucosal healing (MES ≤ 1), and histological healing (GS ≤ 1) rates at each assessment were evaluated. Overall adverse events (AEs) during study period were also evaluated. The impact of IN on mucosal microbial composition was assessed using 16S ribosomal RNA gene sequences. RESULTS: Thirty-three patients were enrolled. The rates of clinical remission at weeks 4, 8, and 52 were 67%, 76%, and 73%, respectively. The rates of mucosal healing at weeks 4 and 52 were 48% and 70%, respectively. AEs occurred in 17 patients (51.5%) during follow-up. Four patients (12.1%) showed severe AEs, among whom 3 manifested acute colitis. No significant alteration in the mucosal microbial composition was observed with IN treatment. CONCLUSIONS: One-year treatment of moderate to severe UC with IN was effective. IN might be a promising therapeutic option for maintaining remission in UC, although the relatively high rate of AEs should be considered.

Active Expression of Genes for Protein Modification Enzymes in Habu Venom Glands.

Genes encoding snake venom toxins have been studied extensively. However, genes involved in the modification and functioning of venom proteins are little known. Protobothrops is a genus of pit vipers, which are venomous and inhabit the Nansei (Southwest) islands of Japan, Taiwan China, Vietnam, Thailand, Myanmar, Nepal, Bhutan, and India. Our previous study decoded the genome of Protobothrops flavoviridis, a species endemic to the Nansei Islands, Japan, and revealed unique evolutionary processes of some venom genes. In this study, we analyzed genes that are highly expressed in venom glands to survey genes for candidate enzymes or chaperone proteins involved in toxin folding and modification. We found that, in addition to genes that encode venom proteins and ribosomal proteins, genes that encode protein disulfide isomerase (PDI) family members (orthologs of human P4HB and PDIA3), Selenoprotein M (SELENOM), and Calreticulin (CALR) are highly expressed in venom glands. Since these enzymes or chaperones are involved in protein modification and potentially possess protein folding functions, we propose that P4HB, SELENOM, CALR, and PDIA3 encode candidate enzymes or chaperones to confer toxic functions upon the venom transcriptome.

The Compositional Structure of the Small Intestinal Microbial Community via Balloon-Assisted Enteroscopy.

INTRODUCTION: An association has been found between human-gut microbiota and various diseases (e.g., metabolic disease) by analyzing fecal or colonic microbiota. Despite the importance of the small intestinal microbiota, sampling difficulties prevent its full analysis. We investigated the composition and metagenomic functions of microbiota along the small intestine and compared them with the microbiota from feces and from other gastrointestinal (GI) sites. METHODS: Mucosal samples from the six GI sites (stomach, duodenum, distal jejunum, proximal ileum, terminal ileum, and rectum) were collected under balloon-assisted enteroscopy. Fecal samples were collected from all participants. The microbial structures and metagenomic functions of the small intestinal mucosal microbiota were compared with those from feces and other GI sites using 16S ribosomal RNA gene sequencing. RESULTS: We analyzed 133 samples from 29 participants. Microbial beta diversity analysis showed that the jejunum and ileum differed significantly from the lower GI tract and the feces (p < 0.001). Jejunal and duodenal microbiotas formed similar clusters. Wide clusters spanning the upper and lower GI tracts were observed with the ileal microbiota, which differed significantly from the jejunal microbiota (p < 0.001). Veillonella and Streptococcus were abundant in the jejunum but less so in the lower GI tract and feces. The metagenomic functions associated with nutrient metabolism differed significantly between the small intestine and the feces. CONCLUSIONS: The fact that the compositional structures of small intestinal microbiota differed from those of fecal and other GI microbiotas reveals that analyzing the small intestinal microbiota is necessary for association studies on metabolic diseases and gut microbiota.

A novel 1-bp deletion variant in DAG1 in Japanese familial asymptomatic hyper-CK-emia.

Asymptomatic hyper-CK-emia (ASCK) is characterized by persistent elevation of creatine kinase (CK) in serum without any neurological symptoms. We ascertained a two-generation family of ASCK patients without clear neurological abnormalities except for the high levels of serum CK (810.5 ± 522.4 U/L). We identified a novel 1-bp deletion variant in the DAG1 gene shared by the patients in the family (NM_001177639: exon 3: c.930delC:p.R311Gfs*70). The variant causes premature termination of translation at codon 477, resulting in a protein product completely devoid of the essential DAG1 domain. Since ASCK has been associated with DAG1 in only one case carrying compound heterozygous missense variants, our new finding of a novel 1-bp deletion revealed the previously unknown dominant effect of DAG1 on ASCK.

Gastric microbiota in patients with Helicobacter pylori-negative gastric MALT lymphoma.

ABSTRACT: To investigate the mucosal microbiota in the stomach of patients with Helicobacter pylori-negative mucosa-associated lymphoid tissue (MALT) lymphoma by means of metagenomic analysis.Although some gastric MALT lymphomas are associated with the presence of H. pylori, other gastric MALT lymphomas occur independently of H. pylori infection. The pathogenesis of H. pylori-negative MALT lymphoma remains unclear.Mucosal biopsy specimens were collected from the gastric body from 33 MALT lymphoma patients with gastric lesions, including both H. pylori-infection naïve patients and posteradication patients, as well as 27 control participants without H. pylori infection or cancer. Subsequently, the samples were subjected to 16S rRNA gene sequencing. Quantitative insights into microbial ecology, linear discriminant analysis effect size, and phylogenetic investigation of communities by reconstruction of unobserved states softwares were used to analyze the participants' microbiota.H. pylori-negative MALT lymphoma patients had significantly lower alpha diversity (P = .04), compared with control participants. Significant differences were evident in the microbial composition (P = .04), as determined by comparison of beta diversity between the 2 groups. Taxonomic composition analysis indicated that the genera Burkholderia and Sphingomonas were significantly more abundant in MALT lymphoma patients, while the genera Prevotella and Veillonella were less abundant. Functional microbiota prediction showed that the predicted gene pathways "replication and repair," "translation," and "nucleotide metabolism" were downregulated in MALT lymphoma patients.H. pylori-negative MALT lymphoma patients exhibited altered gastric mucosal microbial compositions, suggesting that altered microbiota might be involved in the pathogenesis of H. pylori-negative MALT lymphoma.

Detection of novel fusion genes by next-generation sequencing-based targeted RNA sequencing analysis in adenoid cystic carcinoma of head and neck.

OBJECTIVE: Adenoid cystic carcinoma (AdCC) is a rare, indolent salivary gland tumor that is reported to be driven by fusion genes. However, MYB/MYBL1-NFIB fusions have been detected in <60% of all AdCC cases and the oncogenic driver mutations in approximately 40% of AdCC remain unknown. Our aim was to identify novel gene fusions in AdCC. STUDY DESIGN: We investigated 20 AdCC cases using a targeted RNA sequencing panel to identify gene fusions and performed quantitative real-time reverse transcription polymerase chain reaction to assess MYB, MYBL1, and NFIB expression levels. RESULTS: A total of 36 fusion transcripts in 15 cases were detected and validated by Sanger sequencing. The MYB-NFIB and MYBL1-NFIB fusion genes were detected in 9 and 3 cases, respectively, in a mutually exclusive manner. Furthermore, novel gene fusions, namely, NFIB-EPB41L2, MAP7-NFIB, NFIB-MCMDC2, MYBL1-C8orf34, C8orf34-NFIB, and NFIB-CASC20, were identified. Among them, NFIB-EPB41L2 and NFIB-MCMDC2 are thought to activate MYB and MYBL1 expression, respectively, through the insertion of a genomic segment in proximity to MYB and MYBL1 genes, respectively. CONCLUSION: Six novel gene fusions other than MYB/MYBL1-NFIB were identified. The detection of novel fusion genes and investigation of the molecular mechanism will contribute to the development of novel molecular targeted therapies for this disease.

A Japanese hereditary spastic paraplegia family with a rare nonsynonymous variant in the SPAST gene.

Spastic paraplegia (SPG) type 4 is an autosomal dominant SPG caused by functional variants in the SPAST gene. We examined a Japanese family with three autosomal dominant SPG patients. These patients presented with typical symptoms of SPG, such as spasticity of the lower limbs. We identified a rare nonsynonymous variant, NM_014946.4:c.1252G>A [p.Glu418Lys], in all three family members. This variant has previously been reported in a Russian SPG family as a "likely pathogenic" variant.5 Ascertainment of additional patients carrying this variant in an unrelated Japanese SPG family further supports its pathogenicity. Molecular diagnosis of SPG4 in this family with hereditary spastic paraplegia is confirmed.

Familial paroxysmal kinesigenic dyskinesia with a novel missense variant (Arg2866Trp) in NBEA.

Paroxysmal kinesigenic dyskinesia (PKD) is a movement disorder characterized by episodic involuntary movement attacks triggered by sudden movements, acceleration, or intention to move. We ascertained two Japanese familial cases with PKD. The proband is a 22-year-old woman who had noted sudden brief (<30 s) of involuntary movements provoked by kinesigenic trigger such as starting to run, getting on a train, picking up a telephone receiver and so on at the age of 14. Interictal brain single photon emission computed tomography (SPECT) showed hyperperfusion in the left thalamus. A 46-year-old woman, the mother of the proband was also suffering from brief attacks triggered by starting to run in her high school days. On neurological examination, both showed no abnormality. Whole exome sequencing combined with rigorous filtering revealed two heterozygous nonsynonymous variants (NM_001447: c.8976G > C [p.Gln2992His] in FAT2 and NM_015678: c.8596C > T [p.Arg2866Trp] in NBEA). Real time quantitative PCR analysis of Nbea mRNA levels in the developing rat brain revealed peak at postnatal day 28 and decline at postnatal day 56. This result might match the most common clinical course of PKD from the point of view of the most common age at remission. NBEA has been reported to be responsible for neurodevelopmental disease accompanied by epilepsy. We concluded the variant in NBEA most likely to be responsible for our familial cases of PKD.

Ddhd1 knockout mouse as a model of locomotive and physiological abnormality in familial spastic paraplegia.

We have previously reported a novel homozygous 4-bp deletion in DDHD1 as the responsible variant for spastic paraplegia type 28 (SPG28; OMIM#609340). The variant causes a frameshift, resulting in a functionally null allele in the patient. DDHD1 encodes phospholipase A1 (PLA1) catalyzing phosphatidylinositol to lysophosphatidylinositol (LPI). To clarify the pathogenic mechanism of SPG28, we established Ddhd1 knockout mice (Ddhd1[-/-]) carrying a 5-bp deletion in Ddhd1, resulting in a premature termination of translation at a position similar to that of the patient. We observed a significant decrease in foot-base angle (FBA) in aged Ddhd1(-/-) (24 months of age) and a significant decrease in LPI 20:4 (sn-2) in Ddhd1(-/-) cerebra (26 months of age). These changes in FBA were not observed in 14 months of age. We also observed significant changes of expression levels of 22 genes in the Ddhd1(-/-) cerebra (26 months of age). Gene Ontology (GO) terms relating to the nervous system and cell-cell communications were significantly enriched. We conclude that the reduced signaling of LPI 20:4 (sn-2) by PLA1 dysfunction is responsible for the locomotive abnormality in SPG28, further suggesting that the reduction of downstream signaling such as GPR55 which is agonized by LPI is involved in the pathogenesis of SPG28.