Necklace fibers as histopathological marker in a patient with severe form of X-linked myotubular myopathy

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• 作者：Juliana Gurgel-Giannetti^a ; ^{gurgelju@yahoo.com.br} ; Edmar Zanoteli^b ; Eralda Luiza de Castro Concentino^a ; Osorio Abath Neto^b ; Joã ; o Bosco Pesquero^c ; Umbertina Conti Reed^b ; Mariz Vainzof^d
• 关键词：X-linked myotubular myopathy ; Necklace fibers ; MTM1 gene ; Severe neonatal phenotype
• 刊名：Neuromuscular Disorders
• 出版年：2012
• 出版时间：June, 2012
• 年：2012
• 卷：22
• 期：6
• 页码：541-545
• 全文大小：576 K

文摘

X-linked myotubular myopathy due to mutations in the MTM1 gene is classically characterized by a severe neonatal phenotype and a typical muscle biopsy presenting globular and centrally located nuclei in muscle myofibers. Recently, four patients with mild late-onset form have been described, a male with a hemizygous mutation and three females with heterozygous mutations in the MTM1 gene. The muscle biopsies were performed at 13-35 years of age and a new histological marker, the necklace fibers, was described. Here, we report two siblings with the pathogenic c.664 C > T mutation in the MTM1 gene, presenting a severe muscle weakness and respiratory impairment requiring ventilatory support since the first months of life until death, at the age of 36 months and 5 months. In the older brother the muscle biopsy, performed at the age of 30 months, showed almost 100 % of necklace fibers, which were not present in the younger one submitted to muscle biopsy at 5 months of age. Our findings confirm the necklace fibers can be a histopathological finding of MTM1 myopathies, even in the severe neonatal form, and suggest that the necklace fibers appear or increase in number over time.