CGG repeat expansion in LRP12 in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the degeneration of motor neurons. Although repeat expansion in C9orf72 is its most common cause, the pathogenesis of ALS isn't fully clear. In this study, we show that repeat expansion in LRP12, a causative variant of oculopharyngodistal myopathy type 1 (OPDM1), is a cause of ALS. We identify CGG repeat expansion in LRP12 in five families and two simplex individuals. These ALS individuals (LRP12-ALS) have 61-100 repeats, which contrasts with most OPDM individuals with repeat expansion in LRP12 (LRP12-OPDM), who have 100-200 repeats. Phosphorylated TDP-43 is present in the cytoplasm of iPS cell-derived motor neurons (iPSMNs) in LRP12-ALS, a finding that reproduces the pathological hallmark of ALS. RNA foci are more prominent in muscle and iPSMNs in LRP12-ALS than in LRP12-OPDM. Muscleblind-like 1 aggregates are observed only in OPDM muscle. In conclusion, CGG repeat expansions in LRP12 cause ALS and OPDM, depending on the length of the repeat. Our findings provide insight into the repeat length-dependent switching of phenotypes.

A form of muscular dystrophy associated with pathogenic variants in JAG2.

JAG2 encodes the Notch ligand Jagged2. The conserved Notch signaling pathway contributes to the development and homeostasis of multiple tissues, including skeletal muscle. We studied an international cohort of 23 individuals with genetically unsolved muscular dystrophy from 13 unrelated families. Whole-exome sequencing identified rare homozygous or compound heterozygous JAG2 variants in all 13 families. The identified bi-allelic variants include 10 missense variants that disrupt highly conserved amino acids, a nonsense variant, two frameshift variants, an in-frame deletion, and a microdeletion encompassing JAG2. Onset of muscle weakness occurred from infancy to young adulthood. Serum creatine kinase (CK) levels were normal or mildly elevated. Muscle histology was primarily dystrophic. MRI of the lower extremities revealed a distinct, slightly asymmetric pattern of muscle involvement with cores of preserved and affected muscles in quadriceps and tibialis anterior, in some cases resembling patterns seen in POGLUT1-associated muscular dystrophy. Transcriptome analysis of muscle tissue from two participants suggested misregulation of genes involved in myogenesis, including PAX7. In complementary studies, Jag2 downregulation in murine myoblasts led to downregulation of multiple components of the Notch pathway, including Megf10. Investigations in Drosophila suggested an interaction between Serrate and Drpr, the fly orthologs of JAG1/JAG2 and MEGF10, respectively. In silico analysis predicted that many Jagged2 missense variants are associated with structural changes and protein misfolding. In summary, we describe a muscular dystrophy associated with pathogenic variants in JAG2 and evidence suggests a disease mechanism related to Notch pathway dysfunction.

Update on RYR1-related myopathies.

PURPOSE OF REVIEW: RYR1-related myopathy (RYR1-RM) is a group of myopathies caused by mutations in the RYR1 gene, which encodes the ryanodine receptor 1 (RYR1). This review discusses recent advances in the clinical features, pathology, pathogenesis, and therapeutics of RYR1-RM. RECENT FINDINGS: Although treatments such as salbutamol, pyridostigmine, and N-acetylcysteine have been explored as potential therapies for RYR1-RM, none have been conclusively proven to be effective. However, recent clinical trials of Rycal ARM210 in patients with RYR1-RM have shown promising results, including reduced fatigue and improved proximal muscle strength.Recent advances in three-dimensional structural analysis of RYR1 channels, facilitated by cryo-electron microscopy (cryo-EM), have elucidated the distinct molecular mechanisms underlying RYR1 functionality. Additionally, high-throughput screening methods, including FRET-based and endoplasmic reticulum Ca2+-based assays, have been successful in identifying potential candidates for the treatment of RYR1-RM. SUMMARY: Recent advances in clinical and pathological understanding have provided new insights into RYR1-RM. Novel pathomechanisms elucidated by cryo-EM and rapid screening methods have led to the identification of several promising drug candidates. We are hopeful about the potential of Rycal, other new drugs, and gene therapy, offering a promising outlook for the future.

Expansion of GGC Repeat in GIPC1 Is Associated with Oculopharyngodistal Myopathy.

Oculopharyngodistal myopathy (OPDM) is an adult-onset inherited neuromuscular disorder characterized by progressive ptosis, external ophthalmoplegia, and weakness of the masseter, facial, pharyngeal, and distal limb muscles. The myopathological features are presence of rimmed vacuoles (RVs) in the muscle fibers and myopathic changes of differing severity. Inheritance is variable, with either putative autosomal-dominant or autosomal-recessive pattern. Here, using a comprehensive strategy combining whole-genome sequencing (WGS), long-read whole-genome sequencing (LRS), linkage analysis, repeat-primed polymerase chain reaction (RP-PCR), and fluorescence amplicon length analysis polymerase chain reaction (AL-PCR), we identified an abnormal GGC repeat expansion in the 5' UTR of GIPC1 in one out of four families and three sporadic case subjects from a Chinese OPDM cohort. Expanded GGC repeats were further confirmed as the cause of OPDM in an additional 2 out of 4 families and 6 out of 13 sporadic Chinese individuals with OPDM, as well as 7 out of 194 unrelated Japanese individuals with OPDM. Methylation, qRT-PCR, and western blot analysis indicated that GIPC1 mRNA levels were increased while protein levels were unaltered in OPDM-affected individuals. RNA sequencing indicated p53 signaling, vascular smooth muscle contraction, ubiquitin-mediated proteolysis, and ribosome pathways were involved in the pathogenic mechanisms of OPDM-affected individuals with GGC repeat expansion in GIPC1. This study provides further evidence that OPDM is associated with GGC repeat expansions in distinct genes and highly suggests that expanded GGC repeat units are essential in the pathogenesis of OPDM, regardless of the genes in which the expanded repeats are located.

A review of major causative genes in congenital myopathies.

In this review, we focus on congenital myopathies, which are a genetically heterogeneous group of hereditary muscle diseases with slow or minimal progression. They are mainly defined and classified according to pathological features, with the major subtypes being core myopathy (central core disease), nemaline myopathy, myotubular/centronuclear myopathy, and congenital fiber-type disproportion myopathy. Recent advances in molecular genetics, especially next-generation sequencing technology, have rapidly increased the number of known causative genes for congenital myopathies; however, most of the diseases related to the novel causative genes are extremely rare. There remains no cure for congenital myopathies. However, there have been recent promising findings that could inform the development of therapy for several types of congenital myopathies, including myotubular myopathy, which indicates the importance of prompt and correct diagnosis. This review discusses the major causative genes (NEB, ACTA1, ADSSL1, RYR1, SELENON, MTM1, DNM2, and TPM3) for each subtype of congenital myopathies and the relevant latest findings.

Deep convolutional neural network-based algorithm for muscle biopsy diagnosis.

Histopathologic evaluation of muscle biopsy samples is essential for classifying and diagnosing muscle diseases. However, the numbers of experienced specialists and pathologists are limited. Although new technologies such as artificial intelligence are expected to improve medical reach, their use with rare diseases, such as muscle diseases, is challenging because of the limited availability of training datasets. To address this gap, we developed an algorithm based on deep convolutional neural networks (CNNs) and collected 4041 microscopic images of 1400 hematoxylin-and-eosin-stained pathology slides stored in the National Center of Neurology and Psychiatry for training CNNs. Our trained algorithm differentiated idiopathic inflammatory myopathies (mostly treatable) from hereditary muscle diseases (mostly non-treatable) with an area under the curve (AUC) of 0.996 and achieved better sensitivity and specificity than the diagnoses done by nine physicians under limited diseases and conditions. Furthermore, it successfully and accurately classified four subtypes of the idiopathic inflammatory myopathies with an average AUC of 0.958 and classified seven subtypes of hereditary muscle disease with an average AUC of 0.936. We also established a method to validate the similarity between the predictions made by the algorithm and the seven physicians using visualization technology and clarified the validity of the predictions. These results support the reliability of the algorithm and suggest that our algorithm has the potential to be used straightforwardly in a clinical setting.

Intranuclear inclusions in skin biopsies are not limited to neuronal intranuclear inclusion disease but can also be seen in oculopharyngodistal myopathy.

AIMS: Oculopharyngodistal myopathy (OPDM) is caused by the expansion of CGG repeats in NOTCH2NLC (OPDM_NOTCH2NLC) GIPC1 (OPDM_GIPC1), or LRP12 (OPDM_LRP12). Neuronal intranuclear inclusion disease (NIID) is clinically distinct from OPDM but is also caused by the expansion of CGG repeats in NOTCH2NLC, which may be an indicator of intranuclear inclusion in skin biopsy. We investigated the presence of intranuclear inclusions in skin biopsies from patients with OPDM and muscle diseases with a similar pathology to evaluate whether they will have similar diagnostic findings on skin biopsy. METHODS: We analysed the frequency of p62-positive intranuclear inclusions in sweat gland cells, adipocytes and fibroblasts in skin biopsy samples from patients with OPDM (OPDM_NOTCH2NLC [n = 2], OPDM_GIPC1 [n = 6] and OPDM_LRP12 [n = 3]), NIID (n = 1), OPMD (n = 1), IBM (n = 4) and GNE myopathy (n = 2). RESULTS: The p62-postive intranuclear inclusions were observed in all three cell types in both patients with OPDM_NOTCH2NLC and a patient with NIID, in at least one cell type in all six patients with OPDM_GIPC1, and all in three cell types in one of the three patients with OPDM_LRP12. These findings were not observed in patients with OPMD, IBM or GNE myopathy. CONCLUSION: Intranuclear inclusions in skin biopsy samples are not specific to NIID and are found in all three types of genetically confirmed OPDM, suggesting that the underlying mechanism of OPDM may be similar to NIID, regardless of causative genes.

Cerebral blood flow abnormalities with central sparing on arterial spin labeling in mild encephalopathy associated with excitotoxicity: a case report.

BACKGROUND: Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) and mild encephalopathy associated with excitotoxicity (MEEX) are the most frequent acute encephalopathies in pediatric patients in Japan. AESD typically presents with biphasic seizures and delayed reduced diffusion in the subcortical area, called bright tree appearance (BTA), on radiological examination. In patients with AESD, arterial spin labeling (ASL) shows decreased cerebral blood flow (CBF) in the hyperacute stage and increased CBF in the acute stage, suggesting the usefulness of ASL for the early diagnosis of AESD. Additionally, proton magnetic resonance spectroscopy (MRS) shows elevated glutamate (Glu) and glutamine (Gln) in AESD. MEEX is a group of mild encephalopathies with transient elevation of Gln on MRS similar to that in AESD; however, MEEX does not include any clinical biphasic course or abnormalities, including BTA on diffusion-weighted imaging. Although the usefulness of ASL for AESD has been reported, there are no reports for patients with MEEX. In this study, we report our experience with a 4-year-old girl diagnosed with MEEX who showed unique findings on ASL. CASE PRESENTATION: The patient was a 4-year-old girl admitted to the emergency room with febrile status epilepticus. Considering the possibility of AESD, vitamin therapy was initiated. ASL-MR imaging (MRI) of the brain performed on the second day showed increased blood flow in the frontal, temporal, and occipital regions with spared central sulcus, which indicated AESD with central sparing. The patient was diagnosed with AESD, and the treatment included pulse steroid therapy and immunoglobulin therapy from day 3. The patient remained mildly unconscious but gradually became conscious by day 7 with no seizures. Brain MRI performed on day 8 did not show any characteristic AESD findings, such as BTA. Furthermore, MRS showed elevated Gln, which, along with the clinical course, led to the diagnosis of MEEX. The patient was discharged on day 16 without obvious sequelae. CONCLUSIONS: ASL may be useful in the early diagnosis of MEEX as well as AESD, facilitating early intervention.

Subfoveal choroidal thickness after brolucizumab therapy for neovascular age-related macular degeneration: a short-term multicenter study.

BACKGROUND/PURPOSE: Observation of choroidal thickness after anti-vascular endothelial growth factor (VEGF) therapy may be important for the ideal management of neovascular age-related macular degeneration (AMD). This study investigated changes in subfoveal choroidal thickness (SCT) during loading doses of intravitreal injections of brolucizumab in eyes with neovascular AMD. METHODS: This study included 73 eyes of 72 patients with neovascular AMD at five university hospitals in Japan. All 73 eyes underwent three monthly 6.0 mg intravitreal injections of brolucizumab at baseline, 1 month, and 2 months. The SCT at 3 months was evaluated using optical coherence tomography. RESULTS: The 73 eyes were classified into the treatment-naïve group (43 eyes) and the switched group (30 eyes) that were switched from other anti-VEGF treatments. After three intravitreal injections of brolucizumab, SCT significantly decreased from 236.5 ± 98.8 µm at baseline to 200.4 ± 98.3 µm at 3 months (percent of baseline 84.7%, P < 0.001) in the treatment-naïve group. In the switched group, SCT also significantly decreased from 229.0 ± 113.2 µm at baseline to 216.9 ± 110.2 µm at 3 months (percent of baseline 94.7%, P = 0.039), although the decrease was not as marked compared to that of the treatment-naïve group. CONCLUSION: Intravitreal injections of brolucizumab for neovascular AMD significantly reduced the SCT in both the treatment-naïve and switched groups. Brolucizumab may cause significant anatomic changes in the choroid, particularly in treatment-naïve AMD eyes, possibly more than that previously reported for other anti-VEGF agents.

Association of physical prefrailty with prevalence of inadequate nutrient intake in community-dwelling Japanese elderly women: A cross-sectional study.

BACKGROUND AND OBJECTIVES: This study evaluated the association of physical prefrailty with the prevalence of inadequate nutrients among community-dwelling Japanese elderly women. METHODS AND STUDY DESIGN: This cross-sectional study included 120 older women (age range, 65-79 years) at an elders college. Frailty was evaluated using the Japanese version of the Cardiovascular Health Study (J-CHS). Participants were classified as either prefrailty (1-2 deficits) or nonfrailty (0 deficits) based on set criteria. Both groups were compared in terms of physical function, exercise time, nutrient intake, and food group intake estimated by Food Frequency Questionnaire Based on Food Groups (FFQg), and estimated prevalence of inadequate nutrient intake, which was evaluated using each dietary reference value, set as the estimated average requirement (EAR) and dietary goal (DG), based on the Dietary Reference Intakes (DRIs) for Japanese, 2020. RESULTS: Of the participants, 45.0% exhibited physical prefrailty. Binary logistic regression analysis identified that vitamin C intake below EAR (OR, 7.12; 95% CI, 1.47-34.41, p=0.014) was the only factor associated with physical prefrailty. CONCLUSIONS: In addition to measuring physical function, dietary surveys and evaluation of nutritional adequacy by DRIs are expected to be useful for the early prevention of physical prefrailty by linking to nutrition education among community-dwelling Japanese elderly adults.

Anaphylatoxin concentration in aqueous and vitreous humor in the eyes with vitreoretinal interface abnormalities.

The complement system may be activated in the posterior segment of the eye with chorioretinal disease, which may be reflected to the concentration of anaphylatoxins in the aqueous humor. Little is known about the distribution of anaphylatoxins in the aqueous and vitreous humor. The aim of the present study was to investigate the distribution of anaphylatoxin concentration in the aqueous and vitreous humor of the eyes with idiopathic epiretinal membrane or idiopathic macular hole. This was an experimental, observational case series. This study included 43 eyes from 43 patients; 29 eyes with idiopathic epiretinal membrane, and 14 eyes with idiopathic macular hole. All 43 eyes underwent cataract surgery and vitrectomy. The aqueous and vitreous humor were collected at the surgery. The anaphylatoxin concentrations were measured by using a cytometric beads array, and the respective C3a, C4a, and C5a concentrations were 2.003 ± 0.679 (mean ± standard deviation) ng/ml, 1.389 ± 0.419 ng/ml, and 0.003 ± 0.004 ng/ml in the aqueous humor, and 1.236 ± 0.642 ng/ml, 1.250 ± 0.542 ng/ml, and 0.048 ± 0.069 ng/ml in the vitreous humor. The mean C3a concentration in the aqueous humor was significantly higher than in the vitreous humor in 43 eyes of iMH and iERM (P < 0.001). The mean C4a concentration showed no significant difference between the aqueous humor and vitreous humor (P = 0.282), and the mean C5a in the aqueous humor was significantly lower than in the vitreous humor overall (P < 0.001). The C3a concentration in the aqueous humor strongly correlated with that in the vitreous humor (R = 0.510, P < 0.001). The concentrations of C4a and C5a in the aqueous humor moderately correlated with those in the vitreous humor (C4a; R = 0.356, P = 0.019, C5a; R = 0.464, P = 0.022). In conclusion, the anaphylatoxin concentrations measured by cytometric beads array in the aqueous humor may be associated with those measured in the vitreous humor.

Three-year outcome of aflibercept treatment for Japanese patients with neovascular age-related macular degeneration.

BACKGROUND: To evaluate the three-year outcome after intravitreal aflibercept injection (IAI) for neovascular age-related macular degeneration (nAMD). METHODS: Forty-nine treatment-naïve nAMD patients (50 eyes) were enrolled in this prospective study. The eyes received IAI at two-month intervals in the first year. The treatment regimen was changed to IAI based on a treat-and-extend approach in the second and third years. RESULTS: Twenty-nine eyes of 28 patients were successfully followed up over 36 months. The nAMD subtypes included 15 eyes with typical AMD and 14 eyes with polypoidal choroidal vasculopathy. The number of IAIs performed over the 3 years was 17.2 ± 3.1 (mean ± standard deviation). The mean logMAR, which was 0.42 at baseline, improved to 0.19 (P = 0.001) at 12 months, and 0.26 (P = 0.049) at 36 months. The central retinal thickness (CRT) was 329 ± 120 µm at baseline, 151 ± 38 µm (P < 0.001) at 12 months, and 143 ± 61 µm (P < 0.001) at 36 months. The mean subfoveal choroidal thickness (SFCT) was 288 ± 97 µm at baseline, 243 ± 82 µm (P < 0.001) at 12 months, and 208 ± 63 µm (P < 0.01) at 36 months. The changes in logMAR, CRT, and SFCT over the study period did not differ between typical AMD and PCV. CONCLUSION: Long-term aflibercept injection can achieve visual improvement and reduce the thickness of the retina and choroid in nAMD. Morphological improvement of these tissues may not be sufficient to sustain earlier visual improvement over the long-term.

Evidence for Activation of Lectin and Classical Pathway Complement Components in Aqueous Humor of Neovascular Age-Related Macular Degeneration.

PURPOSE: The complement system is activated via 3 different pathways; the lectin pathway (LP), classical pathway (CP), and alternative pathway. To investigate the possible roles for the LP or CP in the development of neovascular age-related macular degeneration (nAMD), we compared aqueous humor levels of complement proteins of the LP and CP between eyes with nAMD and those with cataract as controls. METHODS: Seventeen eyes from 17 patients with treatment-naïve nAMD and 9 eyes from 9 patients with cataract were studied. Aqueous humor samples were collected before intravitreal aflibercept or ranibizumab injection for the nAMD patients and before cataract surgery for the cataract patients. Aqueous humor levels of complement C4 of the LP and CP, complement C3 of all 3 complement pathways, and mannose-binding lectin-associated serine protease (MASP)-2 of the LP were measured by enzyme-linked immunosorbent assay. Aqueous humor levels of C4a and C3a, the activation products of C4 and C3, respectively, were measured by a bead-based immunoassay. The ratios of C4a to C4 and C3a to C3, representing the degree of C4 and C3 activation, respectively, were calculated in individual patients. RESULTS: The aqueous humor levels of C4, C3, and MASP-2 were significantly lower in the nAMD eyes compared to the controls (p = 0.008, p = 0.011, and p = 0.018, respectively). In contrast, the aqueous humor levels of C4a and C3a, as well as the C4a/C4 and C3a/C3 ratios, were significantly higher in the nAMD eyes compared to the controls (p = 0.039, p = 0.003, p < 0.001, and p < 0.001, respectively). CONCLUSIONS: This study provides evidence for significant intraocular activation of either or both of the LP and CP in nAMD eyes that might be involved in the development of nAMD. The significantly lower levels of MASP-2 in the aqueous humor of the nAMD eyes were likely due to MASP-2 consumption by activation of the LP.

A p.Arg499His Mutation in SPAST Is Associated with Infantile Onset Ascending Spastic Paralysis Complicated with Dysarthria and Anarthria.

The complication of anarthria in hereditary spastic paraplegia (HSP) patients has been reported to result from mutations in either ALS2 or FA2H. Here, we present a case of a 12-year-old boy with hereditary spastic paralysis and anarthria associated with a SPAST mutation. Initial presentation was at 14 months of age, when the patient experienced leg stiffness. At 3 years of age, he could speak well using sentences. At 9 years of age, he was found to have dysarthria and had difficulty writing. At 12 years of age, the ability to speak was lost. The patient could not vocalize any words, despite contraction of his neck and respiratory muscles during attempted vocalization. Additionally, the patient has never walked independently in his life. Considering these symptoms, we diagnosed him as having infantile onset ascending hereditary spastic paralysis (IAHSP) complicated with anarthria. By whole-exome sequencing, we discovered a heterozygous SPAST mutation c.1496G > A (p.Arg499His), which was not found in the parents and is probably de novo. This mutation was already repeatedly described with similar phenotype. Our results suggest that the p.Arg499His mutation in SPAST should be considered as a differential diagnosis in IAHSP.