Cardiovascular diseases (CVD) are the leading cause of death all over the world. Beside general risk factors, there are some genetic factors which lead to cardiovascular diseases. Various nuclear DNA mutation and also mitochondrial DNA mutations have been related with cardiovascular diseases. In the present study, a total of 21 samples were collected from different families residing in district Dir. DNA was extracted from buccal epithelial cells using saliva. The mitochondrial tRNA leu (MT TL1) gene was amplified by PCR and 10 samples of different families were sequenced. The sequence was aligned with revised Cambridge Reference Sequence (rCRS) accession # NC-012920.1. It is concluded that cardiovascular diseases in our subjects are not due to mutation in the mitochondrial leucine tRNA gene. However, a large population of subjects with cardiovascular diseases needs to be studied and whole mitochondrial DNA is needed to be sequenced in the subjects with CVD. This will give an idea about the probable DNA marker which can be used to prevent loses due to these diseases at a very early stages.

心血管疾病（CVD）是全世界死亡的主要原因。除了一般危险因素外，还有一些遗传因素会导致心血管疾病。各种核DNA突变以及线粒体DNA突变都与心血管疾病有关。在本研究中，总共从居住在 Dir 区的不同家庭收集了 21 个样本。使用唾液从颊上皮细胞中提取 DNA。通过PCR扩增线粒体tRNA leu (MT TL1)基因，并对不同家族的10个样本进行测序。该序列与修订后的剑桥参考序列 (rCRS) 登录号 # NC-012920.1 进行比对。结论是，我们受试者的心血管疾病不是由线粒体亮氨酸 tRNA 基因突变引起的。然而，需要对大量患有心血管疾病的受试者进行研究，并且需要对患有 CVD 受试者的整个线粒体 DNA 进行测序。这将提供有关可能的 DNA 标记的想法，该标记可用于在早期阶段防止这些疾病造成的损失。