Stanifer John W, Karia Francis, Maro Venance, Kilonzo Kajiru, Qin Xuejun, Patel Uptal D, Hauser Elizabeth R
Department of Medicine, Duke University; Durham, NC United States of America.
Duke Global Health Institute, Duke University; Durham, NC United States of America.
PLoS One. 2017 Jul 21;12(7):e0181811. doi: 10.1371/journal.pone.0181811. eCollection 2017.
In sub-Saharan Africa, approximately 100 million people have CKD, yet genetic risk factors are not well-understood. Despite the potential importance of understanding APOL1 risk allele status among individuals with CKD, little genetic research has been conducted. Therefore, we conducted a pilot study evaluating the feasibility of and willingness to participate in genetic research on kidney disease, and we estimated APOL1 risk allele frequencies among individuals with CKD.
In 2014, we conducted a community-based field study evaluating CKD epidemiology in northern Tanzania. We assessed for CKD using urine albumin and serum creatinine to estimate GFR. We invited participants with CKD to enroll in an additional genetic study. We obtained dried-blood spots on filter cards, from which we extracted DNA using sterile punch biopsies. We genotyped for two single nucleotide polymorphisms (SNPs) defining the APOL1 G1 risk allele and an insertion/deletion polymorphism defining the G2 risk allele. Genotyping was performed in duplicate.
We enrolled 481 participant, 57 (12%) of whom had CKD. Among these, enrollment for genotyping was high (n = 48; 84%). We extracted a median of 19.4 ng of DNA from each dried-blood spot sample, and we genotyped the two APOL1 G1 SNPs and the APOL1 G2 polymorphism. Genotyping quality was high, with all duplicated samples showing perfect concordance. The frequency of APOL1 risk variants ranged from 7.0% to 11.0%, which was similar to previously-reported frequencies from the general population of northern Tanzania (p>0.2).
In individuals with CKD from northern Tanzania, we demonstrated feasibility of genotyping APOL1 risk alleles. We successfully genotyped three risk variants from DNA extracted from filter cards, and we demonstrated a high enrollment for participation. In this population, more extensive genetic studies of kidney disease may be well-received and will be feasible.
在撒哈拉以南非洲地区，约有1亿人患有慢性肾脏病（CKD），但其遗传风险因素尚未得到充分了解。尽管了解CKD患者中载脂蛋白L1（APOL1）风险等位基因状态具有潜在重要性，但相关遗传研究开展较少。因此，我们开展了一项试点研究，评估参与肾脏疾病遗传研究的可行性和意愿，并估计CKD患者中APOL1风险等位基因频率。
2014年，我们在坦桑尼亚北部开展了一项基于社区的现场研究，评估CKD流行病学情况。我们使用尿白蛋白和血清肌酐评估CKD，并估算肾小球滤过率（GFR）。我们邀请CKD患者参加另一项遗传研究。我们从滤纸上获取干血斑，通过无菌打孔活检从中提取DNA。我们对定义APOL1 G1风险等位基因的两个单核苷酸多态性（SNP）以及定义G2风险等位基因的一个插入/缺失多态性进行基因分型。基因分型进行了两次重复操作。
我们招募了481名参与者，其中57人（12%）患有CKD。在这些CKD患者中，基因分型的参与率很高（n = 48；84%）。我们从每个干血斑样本中提取的DNA中位数为19.4纳克，并对两个APOL1 G1 SNP和APOL1 G2多态性进行了基因分型。基因分型质量很高，所有重复样本均显示完全一致。APOL1风险变异的频率在7.0%至11.0%之间，与坦桑尼亚北部普通人群先前报告的频率相似（p>0.2）。
在坦桑尼亚北部的CKD患者中，我们证明了对APOL1风险等位基因进行基因分型的可行性。我们成功地从滤纸上提取的DNA中对三个风险变异进行了基因分型，并证明了较高的参与率。在该人群中，对肾脏疾病进行更广泛的遗传研究可能会受到欢迎且可行。
