Mitochondrial and nuclear genes as the cause of complex I deficiency

Multiple sclerosis (MS) is an immunological inflammatory disease of the central nervous system. The pathogenesis of MS is incompletely understood, but various studies have suggested that mitochondrial dysfunction is associated with the disease. Mitochondria are among the main cellular sources of reactive oxygen and nitrogen species, and they play a pivotal role in many neuro-pathological conditions. The mitochondrial nuclear subunit of complex I gene in mitochondria may play a role in MS, and understanding this role may provide rationale for novel approaches to treatment of the disease and the development of novel therapies. We designed a molecular study to demonstrate biochemical defects in complex I activity and found some novel nucleotide substitutions in mitochondrial DNA that might be involved in the pathogenesis of MS. The mitochondrial complex subunit I sequence was amplified and sequenced in MS patients. Although no reported pathogenic mutations were found in these patients, other studies have clearly indicated that the mitochondrial nuclear complex subunit I gene plays a significant role in MS pathogenesis.

Ataxia-telangiectasia in Iran: clinical and laboratory features of 104 patients

Ataxia-telangiectasia is a multisystem disorder characterized by progressive neurologic impairment, variable immunodeficiency, impaired organ maturation, x-ray hypersensitivity, oculocutaneous telangiectasia, and a predisposition to malignancy. To evaluate clinical and immunologic features of Iranian patients with ataxia-telangiectasia, the records of 104 patients with ataxia-telangiectasia (54 male, 50 female) with the age range of 1.6-23.5 years were reviewed. The Iranian Primary Immunodeficiency Registry was used as the data source. Progressive ataxia was seen in all the patients. Other symptoms were eye movement disorders (n = 84), slurred speech (n = 70), mental retardation (n = 10), and ocular (n = 87) and cutaneous (n = 73) telangiectasia. Three patients developed leukemia and lymphoma, and 17 patients had family history of malignancy. Positive correlation was seen between clinical immunologic symptoms and immunoglobulin deficiencies (P = 0.004). The predominant infections were sinopulmonary and acute and recurrent infections (78 cases). Infections included pneumonia (56 patients), otitis media (34 patients), and sinusitis (50 patients). Average serum alpha-fetoprotein level was 149 +/- 137 ng/dL. The incidence of ataxia-telangiectasia in Iran is high, possibly due to familial marriages. Treatment should be focused on supportive management to prolong survival.