Exome Sequencing Identifies Abnormalities in Glycosylation and ANKRD36C in Patients with Immune-Mediated Thrombotic Thrombocytopenic Purpura
THROMBOSIS AND HAEMOSTASIS
Authors: Basu, Malay Kumar; Massicano, Felipe; Yu, Lijia; Halkidis, Konstantine; Pillai, Vikram; Cao, Wenjing; Zheng, Liang; Zheng, X. Long
Abstract
Background Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a potentially fatal blood disorder, resulting from autoantibodies against ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13). However, the mechanism underlying anti-ADAMTS13 autoantibody formation is not known, nor it is known how genetic aberrations contribute to the pathogenesis of iTTP. Methods Here we performed whole exome sequencing (WES) of DNA samples from 40 adult patients with iTTP and 15 local healthy subjects with no history of iTTP and other hematological disorders. Results WES revealed variations in the genes involved in protein glycosylation, including O-linked glycosylation, to be a major pathway affected in patients with iTTP. Moreover, variations in the ANKRD gene family, particularly ANKRD36C and its paralogs, were also more prevalent in patients with iTTP than in the healthy controls. The ANKRD36 family of proteins have been implicated in inflammation. Mass spectrometry revealed a dramatic alternation in plasma glycoprotein profile in patients with iTTP compared with the healthy controls. Conclusion Altered glycosylation may affect the disease onset and progression in various ways: it may predispose patients to produce ADAMTS13 autoantibodies or affect their binding properties; it may also alter clearance kinetics of hemostatic and inflammatory proteins. Together, our findings provide novel insights into plausible mechanisms underlying the pathogenesis of iTTP.
Analysis of the clinical characteristics of insulin autoimmune syndrome induced by methimazole
JOURNAL OF CLINICAL PHARMACY AND THERAPEUTICS
Authors: Sun, Linli; Fang, Weijin; Yi, Dan; Sun, Wei; Wang, Chunjiang
Abstract
What is known and Objective The number of case reports of insulin autoimmune syndrome (IAS) induced by methimazole (MMI) is increasing. The purpose of this study is to explore the clinical characteristics and provide a scientific reference for clinical diagnosis, treatment and prevention. Methods The literature on IAS cases and case series induced by MMI in Chinese and English was collected for retrospective analysis. Results and discussion A total of 106 patients (males 33, females 73) were described in the Chinese and English literature. The median age of patients with IAS induced by MMI was 37 years (range 15-76) occurring during both regular and irregular MMI therapy or after resumption of medication. The onset of symptoms occurred at night or early morning, within days in some and up to 6 months in others; the symptoms were neuropathic in 65.31% and related to the autonomic nervous system in 33.67%. Blood glucose concentration in samples presumably taken during the hypoglycaemic phase was 1.7 mmol/L (median; range 0.03-4.7); insulin concentrations were elevated >= 100 mU/L (ref range) and associated with low C-peptide levels (<10 mu g/L; ref range). Tests for IgG insulin autoantibodies (IAA) were positive in 104 patients (98.02%) and negative in two patients (1.98%). The 75-g oral glucose tolerance test (OGTT) showed impaired glucose tolerance and diabetic curves. Pancreatic imaging was unremarkable on computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound. Withdrawal of MMI alone or with corticosteroid treatment reduced hypoglycaemic episodes within days to 3 months. IAA decreased and became negative in 3 months (median; range 1-12). Follow-up showed no recurrent hypoglycaemic episodes at 5 months (median; range 1-60). What is new and Conclusion Methimazole-induced IAS is a clinically rare autoimmune disease with hypoglycaemia that occurs during medication treatment that should be treated promptly.