Second Turkish case with MICU1 mutation-related myopathy and extrapyramidal findings

Objectives Mitochondrial Ca+2 hemostasis is the most important signaling pathway on cell death and survival.Decrease in mitochondrial calcium uptake protein 1(MICU1) causes changes in calcium signaling in mitochondria and causes myopathy with extrapyramidal findings which has autosomal recessive pattern of inheritance.Proximal myopathy,learning difficulties,developmental delay and progressive extrapyramidal movement are characteristic clinical findings.Findings such as ataxia,microcephaly,ophthalmoplegia,optic atrophy can also be seen. Methods Here in we present the second case of MICU1 mutation-related myopathy with extrapyramidal findings from Turkey. Results A 13-year-old male patient,who was followed up in another center with the diagnosis of cerebral palsy, autism spectrum disorder and developmental delay was admitted with complaints of frequent falls and gait disturbance. In his neurological examination, global developmental delay,bilateral ptosis,spasticity in the lower extremities, ataxia and dystonic-choreiform movements were observed.The family history was unremarkable except that the parents were cousins. Although laboratory investigations including metabolic screening karyotype, fragile X analysis and brain MRI were normal, moderate elevation of creatine kinase (CK) (588 IU/L) and proximal myopathy by ENMG were detected. Homozygous c.1027A>T (p.K343*) mutation was detected in the MICU gene by whole exome sequencing. The same variant of p.K343* had also been identified in the mother and the brother, but genetic analysis has not been completed from the father of index case. Conclusions MICU1 mutation-related myopathy with extrapyramidal findings is characterized by global developmental delay, ophthalmoplegia, extrapyramidal signs, moderate CK elevation and normal lactate levels. It should be considered in cases that involving more than one system such as other mitochondrial diseases.
Keywords: MICU1,myopathy, extrapyramidal, mitochondria, child