A case report of hereditary myopathy with early respiratory failure caused by new point mutations of TTN gene and literature review
Objective To report the clinicopathological features,gene mutation sites,diagnosis and treatment of a case of hereditary myopathy with early respiratory failure(HMERF),and review the literature to enhance the understanding of the disease.Methods A retrospective analysis was conducted on the clinical data,imaging examinations,histopathological and genetic sequencing results,as well as the diagnosis and treatment of a case of HMERF as the initial presenting symptom,admitted to Sichuan Provincial People's Hospital in April 2021.The clinical characteristics of Chinese patients with HMERF were summarized in conjunction with literature reports.Results This patient presented with limb weakness and progressive dyspnea.Magnetic resonance imaging(MRI)showed selective fat infiltration of the medial head of calf gastrocnemius muscle.Two mutation sites in titin(TTN)gene inherited from both parents were identified,exon 341 c.94828G>A(P.a31610t)and exon 50 c.14915C>T(P.S.4972L),leading to the diagnosis of HMERF.The patient received supportive therapy.The PubMed database was searched and 15 cases of HMERF were diagnosed in Chinese patients over the past decade.The onset age of these patients was(26.1±17.0)years,predominantly affecting males.All patients exhibited mutations in TTN gene.The most prevalent mutation was identified as c.95195C>T(p.P31732L),followed by c.95134T>C(p.C31712R).Conclusions HMERF is a rare genetic disease caused by genetic mutation,with skeletal muscle weakness and respiratory muscle weakness as the main clinical manifestations.Clinical symptoms can be atypical,and exon 344 of TTN gene is a common mutation site.The mutation sites in this case,located at exon 341 c.94828G>A(P.a31610t)and exon 50 c.14915C>T(P.S4972L)of the TTN gene,may represent novel genetic markers for HMERF.
hereditary myopathy with early respiratory failuretitingene mutation