A case of mitochondrial membrane protein-associated neurodegeneration caused by C19orf12 p.Gly58Ser mutation / 中华神经科杂志

ABSTRACT

Neurodegeneration with brain iron accumulation (NBIA) is a group of rare genetic diseases of nervous system. NBIA is characterized by varying degrees of abnormal iron metabolism and excessive iron deposition in brain tissue. The most common symptoms of NBIA are extrapyramidal symptoms. NBIA can also be associated with varying degrees of dysfunction of the pyramidal tract, cerebellum, peripheral nervous system, autonomic nervous system, mental cognition and vision functions. A patient with NBIA admitted to the Department of Neurology of Xijing Hospital in December 2020 was collected and analyzed for clinical features. Whole exome sequencing (WES) was employed to gene mutation screening, and pathogenicity analysis was performed according to the American College of Medical Genetics and Genomics (ACMG) guideline. The patient was a 13-year-old male with a chronic course of disease that began at the age of 4. The first symptom was spastic gait. With the progress of the disease, the patient developed mental retardation, arrhythmia, coughing from drinking water and loss of vision. Magnetic resonance imaging of the head showed atrophy of the optic nerve and hypointensity signal in bilateral substantia nigra and globus pallidus on T 2WI, fluid attenuated inversion recovery sequency, diffusion weighted imaging and susceptibility weighted imaging without "tiger eye sign" which was commonly found in pantothenate kinase associated neurodegeneration. The homozygous mutation c.172G>A (p.Gly58Ser) was found through WES. The proband′s father and mother are cousins (inbreeding), carried heterozygous variation of this locus. This novel mutation was not reported in mutation database. According to ACMG guideline, C19orf12 gene c.172G>A (p.Gly58Ser) was identified for possible pathogenic mutations. The conservative prediction of this locus suggests high conservatism. The final diagnosis of the patient was mitochondrial membrane protein-associated neurodegeneration (MPAN,NBIA type 4). This finding enriched the known mutation database of MPAN and provided a basis for further study of the disease.