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Introduction: Amyloid transthyretin (ATTR) is divided into either hereditary (ATTRv) or sporadic (ATTRwt) and ATTRv is a rare hereditary disease transmitted as an autosomal dominant manner. Its global prevalence is traditionally estimated as 5,000 to 10,000 persons. However, it may be underestimated and the exact prevalence of ATTRv in China mainland remains unknown. Methods: The Genome Aggregation database (gnomAD) database (containing 125,748 exomes) and two genomic sequencing databases--China Metabolic Analytics Project (ChinaMAP) (containing 10588 individuals) and Amcarelab gene database (containing 45392 exomes), were integrated to estimate the prevalence of ATTRv in the world and mainland Chinese populations. Pathogenic variants allele frequency and the prevalence of ATTRv was calculated. Results: Six variants, counting 470 alleles, were defined as pathogenic variants in gnomAD. The prevalence of ATTRv in the world population was 57.4/100,000. Two variants (2 allele counts) and 15 variants (34 individuals) were defined as pathogenic variants in the ChinaMAP database and the Amcarelab exome database, respectively. Thus, the estimated prevalence interval of ATTRv in mainland China was 18.9/100,000-74,9/100,000. Conclusion: The present study demonstrated that the previous prevalence was greatly underestimated using traditional methods. Therefore, raising awareness of the disease is essential for recognizing ATTRv in its early stage.
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Localized peripheral neuropathy amyloidosis is a rare disease that mainly occurred in elder people who present with focal neurological symptoms. AL is the main type of amyloid protein. Biopsy is the golden standard for diagnosis. Mass spectrometry and immunohistochemical analysis help to confirm the type of amyloid protein. This paper retrospectively analyzes the clinical and imaging data, auxiliary examinations, histological, and immunohistochemical markers. The patient, a 34-year-old woman, presented with a right neck mass and weakness of the right arm. Brachial plexus magnetic resonance imaging (MRI) showed a tumor-like lesion in the nerve root at C5 and C6 and in upper trunk. Electrophysiological studies revealed damage in the upper trunk of the brachial plexus. Positive staining with Congo red was found in brachial plexus biopsy. Mass spectrometry showed that the type of amyloid protein was AHL(G-λ). The patient underwent nerve graft for treatment. Meanwhile, literature review revealed that the average onset age of localized spinal nerve amyloidosis was 62.4 years old.The radial nerve was the most susceptible, followed by the lumbosacral plexus. Fifty percent of the type of amyloid protein is AL.Until now, no consolidated treatment is available. Here, we summarize the clinical characteristics of localized peripheral neuropathy amyloidosis in order to raise the awareness of the disease.
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Objective:To investigate the detecting method and clinical characteristics of anti-nodal/paranodal antibodies in chronic inflammatory demyelinating polyradiculopathy.Methods:Serum samples were collected from 212 patients with chronic inflammatory demyelinating polyradiculopathy who were admitted to Huashan Hospital of Fudan University or from other clinical centers from January 2018 to July 2021. Autoantibodies (anti-NF155, anti-NF186, anti-CNTN1) and IgG subtypes were detected with cell-based assay. According to the test results, patients were divided into anti-NF155 positive group, anti-NF186 positive group and anti-CNTN1 positive group, clinical characteristics of patients in each group, including limb weakness, superficial sensation and proprioception, tremor, cerebrospinal fluid protein level, brachial plexus magnetic resonance (MRI) were retrospectively analyzed and compared.Results:A total of 23 patients (10.8%,23/212) were positive for anti-NF155 antibody, 12 (5.7%,12/212) for anti-NF186 antibody, and 4 (1.9%,4/212) for anti-CNTN1 antibody. IgG 4 was the predominant subtype in anti-NF155 and anti-CNTN1 groups. In the anti-NF186 group, all cases were IgG positive and antibody subtypes could be detected in 4 cases (4/12). In anti-NF155 group, 23 patients (100%,23/23) had limb weakness and deep sensory disturbance, 19 patients (82.6%,19/23) had superficial sensory disturbance, 22 patients (95.7%,22/23) were symmetrically involved, 18 patients (78.3%,18/23) showed tremor, 19 patients (19/19) showed abnormal in brachial plexus MRI. In anti-NF186 group, 12 patients had limb weakness (12/12), 9 patients (9/12) and 6 patients (6/12) had superficial sensory disturbance and deep sensory disturbance respectively, 8 patients (8/12) were asymmetrically involved, and only 1 patient (1/12) showed tremor, 1 (1/7) showed abnormal brachial plexus MRI. In anti-CNTN1 group, 4 cases showed symmetrical limb weakness and sensory disturbance, 3 patients had tremor, and four patients showed brachial plexus MRI abnormality. There were statistically significant differences in onset age, proprioception, tremor and MRI abnormalities of brachial plexus among the 3 groups ( P<0.01). Conclusions:The clinical characteristics of CIDP patients with anti-NF155, anti-NF186 and anti-CNTN1 antibodies are different. Screening anti-nodal/paranodal antibodies is of great significance for accurate diagnosis and treatment of patients with peripheral neuropathy.
