John Rebecca, Chapla Aaron, Chacko Geeta, Yoganathan Sangeetha, Thomas Maya Mary, Thomas Nihal
Department of Endocrinology, Diabetes and Metabolism, Christian Medical College, Vellore 632004, India.
Department of Pathology, Christian Medical College, Vellore 632004, India.
JCEM Case Rep. 2025 Mar 26;3(4):luaf020. doi: 10.1210/jcemcr/luaf020. eCollection 2025 Apr.
Mitochondrial diseases have a wide spectrum of clinical presentations. Heteroplasmy, the presence of wild type and mutated mitochondrial deoxyribonucleic acid (DNA) in a single cell, is typical of mitochondrial disorders. It can show varying levels between cells of the same tissue, between organs in a single individual as well as between members of the same family. We describe below a woman who presented to us for management of pancreatic diabetes. Her daughter had a history of recurrent bouts of myopathy; evaluation was suggestive of having a mitochondrial etiology. Subsequently, mitochondrial genetic testing revealed positivity for m.3243A>G variant with a heteroplasmy of 45% in the blood in the daughter and 15% in the proband. We highlight how differences in the heteroplasmy and threshold levels among members of the same family resulted in a variable spectrum of clinical disease. Family screening of members identified with mitochondrial disease is of utmost significance to ensure early diagnosis and therapy.
线粒体疾病有广泛的临床表现。异质性，即单个细胞中野生型和突变型线粒体脱氧核糖核酸（DNA）的存在，是线粒体疾病的典型特征。它在同一组织的细胞之间、单个个体的不同器官之间以及同一家族的成员之间都可能表现出不同的水平。我们在此描述一位因胰腺性糖尿病前来我们处就诊的女性。她的女儿有反复发作的肌病病史；评估提示病因可能是线粒体方面的。随后，线粒体基因检测显示女儿血液中m.3243A>G变异呈阳性，异质性为45%，先证者为15%。我们强调了同一家族成员之间异质性和阈值水平的差异如何导致了临床疾病谱的变化。对确诊为线粒体疾病的家庭成员进行家族筛查对于确保早期诊断和治疗至关重要。
