Jiahong Lu

Clinical features and ETFDH mutation spectrum in a cohort of 90 Chinese patients with late-onset multiple acyl-CoA dehydrogenase deficiency

The major cause of lipid storage myopathies (LSM) in China is multiple acyl-CoA dehydrogenase deficiency (MADD) caused by ETFDH mutations. We here present an analysis of the spectrum of ETFDH mutations in the largest cohort of patients with MADD (90 unrelated patients). We identified 61 ETFDH mutations, including 31 novel mutations, which were widely distributed within the coding sequence. Three frequent mutations were identified: c.250G > A (most common in South China), c.770A > G and c.1227A > C (most common in both South and North China). Regional differences of allele frequency and further haplotype analysis suggest the possibility of founder effects of c.250G > A and c.770A > G. These findings promise to provide the basis for implementing a rapid and economical strategy for diagnosing MADD.

Clinical efficacy and immunological impact of tacrolimus in Chinese patients with generalized myasthenia gravis

In this multicenter, open-label pilot study, the efficacy, safety, and immunological impact of tacrolimus in Chinese patients with generalized myasthenia gravis are assessed. Forty-seven generalized myasthenia gravis (MG) patients were enrolled into this study and given 3mg/day tacrolimus for 24 weeks. The primary efficacy measurements used to monitor response to tacrolimus in MG patients were the Osserman grade, the quantitative MG score (QMGS) recommended by the MGFA, the MG-specific manual muscle testing (MMT) score, and the MG-related activities of daily living (MG-ADL) scale. Also, reduction in steroid doses was used to monitor the effect of tacrolimus. Clinical evaluations were conducted at weeks 4, 8, 12, 16, 20, and 24, while immunological parameters were measured at weeks 4, 12, and 24. Measurements of the Osserman grade, QMGS, MMT, and MG-ADL all suggested improvement in patient health by the fourth week of treatment. Steroid dosage was reduced during the course of the study in 74.2% of the forty-three patients who completed the study. There were thirty-one reported adverse events in the study. Only one was considered serious. We found that tacrolimus reduced levels of the IFN-γ, IL-2, IL-10, and IL-13 cytokines and induced the proliferation of tolerogenic plasmacytoid dendritic cells after treatment. Tacrolimus did not change the population of T cell subtypes but did steadily reduce the population of BAFF-R(+) CD19(+) B cells over the course of the study. Our results show that tacrolimus improves the clinical condition of MG patients and is well tolerated. The decrease in IL-13 and reduction of BAFF-R(+) CD19(+) B cells may be related to the therapeutic effect of tacrolimus.

MOG-antibody associated demyelinating disease of the CNS: A clinical and pathological study in Chinese Han patients

We aim to evaluate the clinical relevance of MOG-ab in a cohort of Chinese Han adults with CNS inflammatory demyelinating diseases (IDDs). MOG-ab and AQP4-ab were examined through a fixed cell based indirect immune-fluorescence assay in 86 patients with CNS-IDDs. MOG-ab was positive in 12 patients, while AQP4-ab was positive in 31 patients; none double positives. Optic neuritis (ON) was the most frequent symptom at onset (75.0%) or during the whole disease course (83.3%) of MOG-ab associated IDDs (MOG-IDDs); 79.5% of the episodes involved only the optic nerve in MOG-IDDs. MOG-ab related ON (MOG-ON) usually caused severe visual impairment, longitudinally extensive optic nerve lesion with anterior enhancement and perineural soft tissue enhancement, responded well to steroid, but still could leave remarkable thinning of retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC). MOG-IDDs had less spinal cord involvement compared to AQP4-ab mediated NMO/SD. Heterogeneous brain lesions existed in 66.7% of the patients with MOG-IDDs. Large, edematous white matter lesions were observed with the pathological feature of obvious demyelination yet preservation of astrocyte and axon, fundamentally different from the astrocytopathy typically seen in NMO/SD. Our investigations suggest that MOG-ab mediates a distinct disease entity separate from NMO/SD.

Muscle pathology and whole-body MRI in a polyglucosan myopathy associated with a novel glycogenin-1 mutation

We report a 46-year-old female with late-onset skeletal myopathy affecting proximal limb muscles. Muscle biopsy revealed a polyglucosan myopathy with PAS-positive inclusions predominantly in glycogen-depleted fibers, which were demonstrated as type I fibers by ATPase staining. Whole-body magnetic imaging disclosed that the paravertebral, scapular, and pelvic girdle muscles, the anterior compartment of the arms, and the posterior compartment of the thighs were preferentially involved. Genetic analysis revealed a homozygous novel mutation in exon 6 of the glycogenin-1 gene (GYG1) (c.634C>T, p.His212Tyr). Protein analysis revealed normal levels of glycogenin-1 even before alpha-amylase digestion indicating preserved protein expression but impaired glucosylation. In vitro functional assay demonstrated that this variant impaired the autoglucosylating ability resulting in a non-functional protein. We report a glycogenin-1 related myopathy with a distinct histopathology and unique muscle imaging pattern.

HLA-DQA1*03:02/DQB1*03:03:02 is strongly associated with susceptibility to childhood-onset ocular myasthenia gravis in Southern Han Chinese☆

OBJECTIVE Our aim was to investigate the correlation between onset age, clinical features and HLA-DQA1/DQB1 genetic variability in myasthenia gravis (MG) patients in Southern Han Chinese. METHODS 205 MG patients and 100 controls were genotyped for HLA-DQA1 and -DQB1 using sequence-based typing (SBT) and analyzed for haplotype frequencies. Anti-acetylcholine receptor (AChR) autoantibodies were measured in all, and muscle-specific tyrosine kinase (MuSK) antibodies were tested in AChR antibody negative patients. RESULTS HLA-DQA1/DQB1 haplotypes showed association only with childhood-onset MG. Haplotype DQA1*03:02/DQB1*03:03:02 (DQ9) was positively associated with the childhood-onset MG, while haplotype DQA1*02:01/DQB1*02:02 and DQA1*05:01:01/DQB1*02:01:01 (DQ2) were negatively associated with this group. Childhood-onset ocular MG patients had an extremely high phenotype frequency of DQ9 haplotype (90.1% of patients, 34.0% of controls, p≤0.0001, OR=17.8). CONCLUSIONS The childhood-onset ocular MG in Southern Han Chinese may present a particular subgroup of distinct genetic background. Its correlation to the HLA haplotype DQA1*03:02/DQB1*03:03:02 might explain the phenotypic difference of MG between Han Chinese and Caucasians.

Novel mutations m.3959G>A and m.3995A>G in mitochondrial gene MT-ND1 associated with MELAS.

Abstract Mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) are progressive neurodegenerative disorder associated with polygenetic, maternally inherited mutations in mitochondrial DNA. Approximately 80% of MELAS cases are caused by the mutation m.3243A>G of the mitochondrial tRNALeu (UUR) gene (MT-TL1). We reported two probands with MELAS features. Muscle biopsy identified ragged-red fibers (RRF) in Gomori Trichrome staining. A respiratory chain function study showed decreased activity of mitochondrial respiratory chain complex I in both probands. Sequencing of the mitochondrial DNA revealed two novel MT-ND1 gene missense mutations, m.3959G>A and m.3995A>G, which are highly conserved among species. Protein secondary structure predictions demonstrated that these mutations may alter the peptide structure and may lead to decreased ND1 gene stability. Our findings suggest that these two novel mutations may contribute to the MELAS phenotypes of the patients in our study.

Double filtration plasmapheresis benefits myasthenia gravis patients through an immunomodulatory action.

Double filtration plasmapheresis (DFPP) is used to treat myasthenia gravis (MG). However, the definite mechanism is unclear. This study investigated whether DFPP improves MG through an immunomodulatory action. Thirty-five MG patients were randomly divided into two treatment groups: Group A (DFPP combined with oral methylprednisolone) and Group B (oral methylprednisolone alone). Their antibody levels, clinical scores, cytokine levels, and CD4(+)CD25(high)Foxp3(+) (regulatory T cell [Treg]) levels were then determined. Anti-titin antibody levels were significantly lower in Group A compared with Group B after treatment. The clinical remission rate in Group A was significantly higher than in Group B. The changes in cytokine levels (interleukin [IL]-2, IL-4, IL-10, and interferon-γ) in sera and the peripheral blood mononuclear cell culture supernatants did not significantly differ before and after the treatments in both groups (p<0.05). The soluble intercellular adhesion molecule-1 (sICAM-1) levels were lower in Group A than in Group B (p<0.05). MG patients exhibited a lower percentage of Treg cells than normal patients. DFPP combined with methylprednisolone treatment increased the Treg cell percentage more than treatment with methylprednisolone alone (p<0.05). DFPP treatment more effectively lowers sICAM-1 and increases Treg cell expression, consequently benefiting MG patients.

Clinical and pathological features in 15 Chinese patients with calpainopathy.

Background: Calpainopathy is comprised of a group of myopathies caused by deficiency in calcium‐activated, neutral protease (calpain‐3). In this study we identify calpainopathy in a cohort of Chinese patients with unclassified myopathy and analyze its clinical and pathological features. Methods: Sixty‐six muscle biopsies were selected for combined Western blotting of dysferlin and calpain‐3 after immunohistochemical staining. Clinical and pathological parameters of 15 confirmed calpainopathy cases were determined. Results: The diagnosis of calpainopathy in 15 Chinese patients was confirmed by Western blot analysis. Fourteen subjects had progressive proximal muscle weakness; 1 presented with bilateral distal muscle atrophy of the lower extremities. Scapular winging was observed in 12 patients (80%), and joint contractures were found in 10 others (66.7%). Histopathological studies showed a high prevalence of lobulated fibers (66.7%). Conclusions: Chinese patients with calpainopathy share some common clinical and pathological features with the reported characteristics of non‐Chinese patients. Muscle Nerve, 2011

Novel mutations in the C-terminal region of GMPPB causing limb-girdle muscular dystrophy overlapping with congenital myasthenic syndrome

Mutations in the GMPPB gene may underlie both limb girdle muscular dystrophy (LGMD) and congenital myasthenic syndrome (CMS). Forty-one cases have been reported to date and hotspot mutations are emerging in the Caucasian population. Clinical and pathological features of 5 patients with compound heterozygous GMPPB mutations were collected and retrospectively reviewed. In vitro functional analysis was performed to investigate the pathogeneity of GMPPB variants. The patients presented with proximal limb weakness in their first to second decades. Fluctuating muscle weakness, myalgia and calf hypertrophy were the major complaints. Myogenic changes on electromyography and marked attenuation on 3 Hz repetitive nerve stimulation were observed in all patients. Four reported a beneficial response to pyridostigmine. Muscle MRI showed selective involvement in the calf in case 1. Immunolabeling of α-dystroglycan was abnormal for case 1 and case 2. Four novel missense mutations in the C-terminal region of GMPPB were identified, with p.(Arg357His) being present in all the cases. In vitro functional assays demonstrated that these variants did not markedly reduce the amount of GMPPB, but gave rise to an increased propensity for protein aggregation. Increasingly, patients with GMPPB mutations are found to present with an overlapping LGMD/myasthenic syndrome. The mutation spectrum in Chinese patients may differ from that of European populations, with the mutation p.(Arg357His) most frequently found. These mutations may lead to abnormal folding of GMPPB leading to protein aggregates in the cytoplasm rather than an overall loss in protein expression.

Clinical heterogeneity and a high proportion of novel mutations in a Chinese cohort of patients with dysferlinopathy.

BACKGROUND AND AIMS Dysferlinopathies are a group of autosomal recessive muscular dystrophies caused by mutations in the dysferlin gene. This study presents clinical features and the mutational spectrum in the largest cohort of Chinese patients analyzed to date. PATIENTS AND METHODS A total of 36 unrelated Chinese patients with diagnostic suspicion of dysferlinopathy were clinically and genetically characterized. RESULTS Patients were divided into five phenotypes: 19 patients with limb girdle muscular dystrophy (LGMD) type 2B, 10 with Miyoshi myopathy (MM), 1 with distal anterior compartment myopathy (DACM), 3 with exercise intolerance, and 3 with asymptomatic hypercreatine phosphokinasemia (hyperCPKemia). Thirty-one patients showed an absence or drastic reduction of dysferlin expression by Westernblot. Forty-three mutations were identified in DYSF, including 31 novel. CONCLUSION Our study underlines clinical heterogeneity and a high proportion of novel mutations in Chinese patients affected with dysferlinopathy.