Point Mutations on Mitochondrial DNA in Iranian Patients with Friedreich’s Ataxia

ObjectiveMitochondrial DNA (mtDNA) is considered a candidate modifier factor for neuro-degenerative disorders. The most common type of ataxia is Friedreich's ataxia (FA). The aim of this study was to investigate different parts of mtDNA in 20 Iranian FA patients and 80 age-matched controls by polymerase chain reaction (PCR) and automated DNA sequencing methods to find any probable point mutations involved in the pathogenesis of FA.Materials and MethodsWe identified 13 nucleotide substitutions including A3505G, T3335C, G3421A, G8251A, A8563G, A8563G, G8584A, T8614C, T8598C, C8684T, A8701G, G8994A and A9024G.ResultsTwelve of 13 nucleotide substitutions had already been reported as polymorphism. One of the nucleotide substitutions (A9024G) had not been reported before. The A9024G nucleotide substitution does not change its amino acid. The controls were also investigated for this polymorphism which was found in two of them (2.5%).ConclusionNone of the mutations found in this study can affect the clinical manifestations of FA. This survey also provides evidence that the mtDNA A9024G allele is a new nonpathogenic polymorphism. We suggest follow-up studies for this polymorphism in different populations.

Application of multiplex PCR with histopathologic features for detection of familial breast cancer in formalin-fixed, paraffin-embedded histologic specimens

Breast cancer is the most common malignancy among females in the world. Age and familial history are the major risk factors for the development of this disease in Iran. Mutations of BRCA1 and BRCA2 genes are associated with a greatly increased risk for development of familial breast cancer. Frequency of BRCA mutations was identified in familial breast cancers (FBC) and non familial breast cancers (NFBC) by molecular genetics, morphological and Immunohistochemical methods. Thirty forth formalin fixed, paraffin embedded breast tissue tumors were analyzed from 16 patients with FBC and 18 patients with NFBC. Three 5382insC mutations detected by multiplex PCR in 16 familial breast cancers. Immunohistochemical method was used to detect estrogen receptor (ER) and progesterona receptor (PR) and TP53. Comparison of ER, PR and TP53 exhibited high difference (P < 0.0001) in familial breast cancers and nonfamilial breast cancers. Our results demonstrated that 5382insC mutation, ER, PR, TP53, mitotic activity, polymorphism, necrosis and tubules can serve as the major risk factors for the development of FBC.Рак молочної залози (РМЗ) є найбільш частим видом злоякісних пухлин у жінок в світі. В Ірані вік та наявність захворювань РМЗ в найближчих родичів є головними факторами ризику розвитку цього захворювання. Мутації гена BRCA1/2 зумовлюють високий ризик розвитку протягом життя РМЗ. Досліджено частоти мутацій ВRCA в осіб з сімейним раком молочної залози (СРМЗ) та несімейним раком молочної залози (НСРМЗ) з Ірану. Для досягнення поставленої цілі використовували молекулярно-генетичні, морфологічні та імуногістохімічні методи. Проаналізовано 34 тканини пухлин, зафіксованих в парафіні, у 16 хворих СРМЖ і 18 хворих НСРМЖ. При дослідженні генів ВRCA1 та ВRCA2 з мультиплексним ПЦР ідентифіковано три мутації (538insC) в 16 хворих СРМЖ. Імуногістохімічним методом визначали рецептор естрогена (ЕР), рецептор прогестерона (РП) і ТР53. Порівняння ЕР, РП і ТР53 в тканинах СРМЖ та НРМЖ показало високі достовірні відмінності (Р < 0.0001). В результаті досліджень виявлено, що мутація 5382insC, ЭР, РП, TP53, мітотична особливість, поліморфізми, некроз і тубули можуть бути використані як головні фактори ризику розвитку СРМЖ.Отмечено, что рак молочной железы (РМЖ) является наиболее частым видом злокачественных опухолей у женщин в мире. В Иране возраст и наличие заболеваний РМЖ у ближайших родственников являются главными факторами риска развития этого заболевания. Мутации гена BRCA1/2 обусловливают высокий риск развития в течение жизни РМЖ. Исследованы частоты мутаций BRCA у лиц с семейным РМЖ (СРМЖ) и несемейным РМЖ (НСРМЖ) из Ирана. Для достижения поставленной цели использованы молекулярно-генетические, морфологические и иммуногистохимические методы. Проанализированы 34 ткани опухолей, зафиксированных в парафине, у 16 больных СРМЖ и 18 больных НСРМЖ. При исследовании генов BRCA1 и BRCA2 с мультиплексным ПЦР идентифицированы три мутации (5382insC) у 16 больных СРМЖ. Иммуногистохимическим методом определены рецепторы эстрогена (ЭР), прогестерона (РП) и ТР53. Сравнение ЭР, РП и ТР53 в тканях СРМЖ и НРМЖ показало высокие достоверные различия. В результате исследований выявлено, что мутация 5382insC, ЭР, РП, ТР53, митотическая особенность, полиморфизмы, некроз и тубулы можно использовать как главные факторы риска развития СРМЖ

Mitochondrial DNA haplogroups in Kuwaiti infertile males.

A variety of mtDNA mutations responsible for human diseases have been associated with molecular defects in the OXPHOS system. It has been proposed that mtDNA genetic alterations can also be responsible for sperm dysfunction. To investigate any possible association between infertility and mtDNA haplogroups (hg), the nucleotide sequence of the Hypervariable Segment I (HVS-I) of mtDNA was determined in 99 unrelated Kuwaiti patients with infertility and 64 normal controls with the same ethnicity. DNA was extracted from the peripheral blood after having obtained informed consent. The nucleotide sequence of HVS-I (np 16,024-16,383) was directly determined. High-resolution RFLP analysis and control-region sequencing revealed high proportion of haplogroup J and M in normal controls (64% and 20.3%) compared to infertile men (26.2% and 8.1%) respectively. (P= 0.002 for J and 0.03 for M) Therefore, we hypothesize that individuals classified as haplogroup J and M demonstrate a significant decrease in risk of infertility in Kuwaiti population

Identification of a new human mtDNA polymorphism (A14290G) in the NADH dehydrogenase subunit 6 gene

Leber's hereditary optic neuropathy (LHON) is a maternally inherited form of retinal ganglion cell degeneration leading to optic atrophy in young adults. Several mutations in different genes can cause LHON (heterogeneity). The ND6 gene is one of the mitochondrial genes that encodes subunit 6 of complex I of the respiratory chain. This gene is a hot spot gene. Fourteen Persian LHON patients were analyzed with single-strand conformational polymorphism and DNA sequencing techniques. None of these patients had four primary mutations, G3460A, G11788A, T14484C, and G14459A, related to this disease. We identified twelve nucleotide substitutions, G13702C, T13879C, T14110C, C14167T, G14199T, A14233G, G14272C, A14290G, G14365C, G14368C, T14766C, and T14798C. Eleven of twelve nucleotide substitutions had already been reported as polymorphism. One of the nucleotide substitutions (A14290G) has not been reported. The A14290G nucleotide substitution does not change its amino acid (glutamic acid). We looked for base conservation using DNA star software (MEGALIGN program) as a criterion for pathogenic or nonpathogenic nucleotide substitution in A14290G. The results of ND6 gene alignment in humans and in other species (mouse, cow, elegans worm, and Neurospora crassa mold) revealed that the 14290th base was not conserved. Fifty normal controls were also investigated for this polymorphism in the Iranian population and two had A14290G polymorphism (4%). This study provides evidence that the mtDNA A14290G allele is a new nonpathogenic polymorphism. We suggest follow-up studies regarding this polymorphism in different populations