Background: Leigh syndrome (LS) is a rare and inherited disease which is associated with progressive neurological disorders. The molecular underlying mechanism in LS is defined with some defects in mitochondrial respiratory chain enzymes. Case presentation: Here, an 8-year-old girl is reported with bilateral horizontal gaze palsy, ataxia and drowsiness. She developed unsteady gait, drowsiness, progressive ataxia and intention tremor during her admission period. The laboratory tests were reported within normal values including biochemical, hematological, immunological, infectious and inflammatory markers and blood and cerebrospinal fluid (CSF) lactate. Brain magnetic resonance imaging (MRI) demonstrated dorsal midbrain, bilateral putamen nuclei and cerebellar dentate nucleus involvement. Ocular examination revealed retinal atrophy and pale disk in both sides. These symptoms were in favor of a neurodegenerative disorder. Magnetic resonance spectroscopy (MRS) revealed an elevated lactate peak in involved areas which suggested a mitochondrial disease. Finally, the molecular genetic test reported NDUFS4 gene mutation which confirmed the presence of Leigh syndrome. She responded significantly to mitochondrial treatment cocktail and clinical signs and symptoms improved gradually. NDFUS4 gene encodes a subunit of mitochondrial complex I (NADH: ubiquinone oxidoreductase) that removes electrons from NADH and transfers them to the electron acceptor ubiquinone. Conclusion: Our findings indicated that various symptoms and clinical features can be found in Leigh syndrome which could be probably due to different mutations in mitochondrial genes. Therefore, appropriate clinical and laboratory settings along with brain MRI, MRS and genetic test analysis would be necessary for the early diagnosis.

Introduction: Duchenne muscular dystrophy (DMD) is the most common muscular dystrophy in the pediatric population. The manifestations are progressive muscle weakness, impairment in walking and motor function leading to loss of ambulation by age of 13 years. Molecular studies are standard tests for diagnosis. This article describes the status of disease progression and genetic pattern in the Iranian affected boys and furthermore, concerns to find a correlation between the genotype and motor function phenotype of them. Methods This study was performed on 152 DMD patients. Clinical history including disease phenotype, steroid therapy data and the NorthStar Ambulatory Assessment (NSAA) score were all collected. Molecular diagnoses were confirmed by multiplex ligation dependent probe amplification and Next Generation Sequencing tests. Results We studied a total of 152 Iranian DMD patients. The mean age at disease onset was 4.04 ± 2.00 year and the mean age at diagnosis was 5.05 ± 2.08 year. The mean age of loss of ambulatory was 10.9 year. Contracture was seen in 38.9 %. The overall mean of NSAA total score versus age of the patients peaked at 4 year with mean NSAA score of 24. We assessed the yearly changes in the NSAA linear score for all cases based on mutation type and exon site. We found deletion mutation in 79.1%, duplication in 6.8%, nonsense in 12.8%, and splice site in 1.4%. The most common single exon was deletion exon 44 in our patients (5.3%) and the most common multiexon deletion was 45–50 and 45–52 exon equally with 4.6%. This study did not show any correlation between age at disease onset, loss of ambulation age and wheelchair dependency with mutation type but a correlation between contracture with mutation type was found. A significant deference in NSAA score were seen between deletion and nonsense groups at the age of 3 year (P = 0.036) and 3.5 years (p = 0.04). We couldn’t find any correlation among phenotype and Exon site. 91.1% had a history of corticosteroid taking and 54.1% of patient had compliance with rehabilitation. Conclusion This study has demonstrated the phenotype and mutational features of DMD boys and provide information of the disease natural motor history, disease progression and disease diagnosis with the management status of DMD in Iran. Achieved data will encourage the development of clinical trials and advance future molecular therapies in Iran.