Late-onset pompe disease in Iran: A clinical and genetic report.

INTRODUCTION: Pompe disease is characterized by absence or deficiency of acid α-glucosidase, and several causative mutations are known. In this study we report clinical and laboratory data in Iranian patients with late-onset Pompe disease (LOPD), focusing on population-specific mutations. METHODS: Clinical and laboratory data of 14 patients from 10 families with the diagnosis of LOPD were recorded. All had reduced enzyme activity on dried blood spot (DBS) analysis. Genetic investigation was performed to identify the underlying mutations. RESULTS: The age of onset ranged from <2 to 38 years. The clinical presentations were heterogeneous. Two siblings presented with foot drop. The most common mutation was c.(-32-13T>G). There were 4 novel mutations: c.(2040 + 2dup); c.(1650delG); c.(1837T>G); and c.(2596delG). CONCLUSION: This is a comprehensive report of LOPD in Iranian patients. Distinct phenotypic and genotypic features in this population are highlighted. Muscle Nerve 55: 835-840, 2017.

Electrophysiological studies in patients with seropositive/seronegative myasthenia gravis.

Background: Myasthenia gravis (MG) affects the neuromuscular transmission, causing fluctuating muscle weakness and fatigue. This study is carried out with the aim to study the electrophysiologic findings of different subtypes of MG referred to our center in Tehran, Iran. Methods: All patients with MG presenting to neurology department of Shariati Hospital, Tehran University of Medical Sciences were enrolled. Clinically, patients with MG were categorized as ocular vs. generalized. The acetylcholine receptor (Ach-R) and muscle-specific receptor tyrosine kinase (anti-MuSK) antibodies were performed. Repetitive Nerve Stimulation (RNS) was performed using the standard method, with supramaximal stimulation of muscles at the 3 Hz frequency by surface electrode at rest. Abductor pollicis brevis (APB) (median nerve), anconeus (radial nerve), trapezius (accessory nerve), and nasalis (facial nerve) muscles were studied in all patients. Single fiber electromyography (SFEMG) was performed by standard method. Results: 196 seropositive patients with MG were included in the study. In electrophysiological studies, RNS was performed for 146 patients of Ach-R-Ab positive MG, with positive results in 110 patients. In addition, SFEMG was conducted for 8 patients with negative RNS, which resulted in 7 positive tests. Among 23 patients with anti-MuSK-positive MG, RNS was performed for 16 patients, with positive results in 11 patients. The 5 remaining patients with negative RNS test were studied by SFEMG, 4 of whom had positive results. APB compound muscle action potential (CMAP) decrementation significantly correlated with Ach-R-Ab positive MG (P < 0.03). Conclusion: This finding can support the hypothesis that the selection of muscles in electrodignostic study would be important. The electrodiagnostic studies are a good and non-invasive diagnostic tool for MG, and a combination of different distal, proximal, and facial muscles can increase the overall sensitivity of the test.

Distinct Clinical and Genetic Findings in Iranian Patients With Glycogen Storage Disease Type 3.

OBJECTIVES: Glycogen storage disease type 3 (GSD-III) is a rare inherited metabolic disorder caused by glycogen debranching enzyme deficiency. Various pathogenic mutations of the AGL gene lead to abnormal accumulation of glycogen in liver, skeletal, and cardiac muscles. Here, we report distinct clinical and genetic data of Iranian patients with GSD-III. METHODS: Clinical and laboratory data of 5 patients with GSD-III were recorded. Genetic investigation was performed to identify the causative mutations. RESULTS: Three patients had typical liver involvement in childhood and one was diagnosed 2 years after liver transplantation for cirrhosis of unknown etiology. Four patients had vacuolar myopathy with glycogen excess in muscle biopsy. All patients had novel homozygous mutations of the AGL gene namely c.378T>A, c.3295T>C, c.3777G>A, c.2002-2A>G, and c.1183C>T. CONCLUSIONS: This is the first comprehensive report of patients with GSD-III in Iran with 2 uncommon clinical presentations and 5 novel mutations in the AGL gene.

What is Susac syndrome? - A brief review of articles.

Susac's syndrome (SS) is a clinical triad of encephalopathy, branch retinal artery occlusion and sensorineural hearing loss and maybe due to an immune-mediated endotheliopathy. Because of its rarity and some similarities to other common neurological conditions such as multiple sclerosis and acute disseminated encephalomyelitis, it is often misdiagnosed and therefore mistreated. To the best of our knowledge, there is only one case report from our country with this diagnosis. Here, we have a short discussion on this issue to introduce it to our colleagues and remind it as a differential diagnosis in patients with unexplained encephalopathy.