IRCCS Casa Sollievo della Sofferenza, U.O. Genetica Medica, Viale Padre Pio, 71013 San Giovanni Rotondo (FG), Italy.
Mol Genet Metab. 2010 Jan;99(1):42-52. doi: 10.1016/j.ymgme.2009.09.001.
Cystinuria is a rare inherited disorder characterized by defective renal reabsorption of cystine and the dibasic amino acids. SLC3A1 and SLC7A9 have been identified as responsible genes. The large majority of the more than 200 mutations so far identified in the two genes are point mutations, while only few alleles carrying gross genomic alterations have been reported. We screened 39 cystinuric patients for large rearrangements, by two home-made multiplex ligation-dependent probe amplification (MLPA) assays. MLPA analysis led to the identification of 6 different alleles in SLC3A1 and 2 in SLC7A9 accounting for a total of 25 copy number changes, 11 in SLC3A1 and 14 in SLC7A9. Three large rearrangements in SLC3A1, deletion of exons 2-4 (E2_E4del), deletion of exons 5-6 (E5_E6del) and duplication of exons 8-9 (E8_E9dup) are novel. A complete SLC7A9 gene deletion was found in three patients. In addition, we report the identification of three novel point mutations in SLC7A9 (p.G105E, p.R250K, c.1416_1417insAC), the frequency and the occurrence of cystinuria mutations in a cohort of 172 Italian patients. In conclusion, we developed a reliable and robust MLPA analytic method for SLC3A1 and SLC7A9 genes that represents an optimal complement to DNA sequence analysis in patients with cystinuria, enabling the screening for deletions and duplications.
胱氨酸尿症是一种罕见的遗传性疾病，其特征是胱氨酸和二碱基氨基酸的肾脏重吸收缺陷。SLC3A1 和 SLC7A9 已被确定为致病基因。迄今为止，在这两个基因中已发现超过 200 种突变，绝大多数是点突变，而只有少数携带大片段基因组改变的等位基因已被报道。我们通过两种自制的多重连接依赖性探针扩增（MLPA）检测法，对 39 名胱氨酸尿症患者进行了大片段重排的筛查。MLPA 分析导致在 SLC3A1 中鉴定出 6 种不同的等位基因，在 SLC7A9 中鉴定出 2 种，共占 25 种拷贝数变化，其中 11 种在 SLC3A1 中，14 种在 SLC7A9 中。SLC3A1 中的 3 种大的重排，包括外显子 2-4（E2_E4del）缺失、外显子 5-6（E5_E6del）缺失和外显子 8-9（E8_E9dup）重复，均为新发现。在 3 名患者中发现了完全的 SLC7A9 基因缺失。此外，我们还报告了在 SLC7A9 中发现了 3 种新的点突变（p.G105E、p.R250K、c.1416_1417insAC），在 172 名意大利患者的胱氨酸尿症突变频率和发病情况。总之，我们开发了一种针对 SLC3A1 和 SLC7A9 基因的可靠而强大的 MLPA 分析方法，它是胱氨酸尿症患者 DNA 序列分析的理想补充方法，能够进行缺失和重复的筛查。
