Bendavid Claude, Kleta Robert, Long Robert, Ouspenskaia Maia, Muenke Maximilian, Haddad Bassem R, Gahl William A
Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, 10 Center Drive, MSC 1851 Building 10, Room 10C-103, Bethesda, MD 20892-1851, USA.
Hum Genet. 2004 Nov;115(6):510-4. doi: 10.1007/s00439-004-1170-2. Epub 2004 Sep 9.
Cystinosis is an autosomal recessive lysosomal storage disease caused by mutations in CTNS. The most prevalent CTNS mutation, a 57-kb deletion, occurs in approximately 60% of patients in the United States and northern Europe and removes exons 1-9, most of exon 10, the CTNS promoter region, and all of an adjacent gene of unknown function called CARKL. CTNS codes for the lysosomal cystine transporter, whose absence leads to intracellular cystine accumulation, widespread cellular destruction, renal Fanconi syndrome in infancy, renal glomerular failure in later childhood, and other systemic complications. Because treatment with oral cysteamine can prevent or delay these complications significantly, early and accurate diagnosis is critical. This study describes the generation of fluorescence in situ hybridization (FISH) probes for the 57-kb deletion in CTNS, enabling cytogenetics laboratories to test for this common mutation. The probes would also be able to detect a less frequent 11.7-kb deletion. A blinded study was performed using multiplex PCR analysis as the gold standard to determine the presence or absence of the 57-kb deletion. The FISH probes, evaluated on 12 lymphoblastoid cell lines from singly deleted, doubly deleted, and nondeleted patients, made the correct diagnosis in every case. This appears to be the first FISH-based diagnostic method described for any lysosomal storage disorder. It can assist in the antenatal and perinatal diagnosis of cystinosis and promote earlier salutary therapy with cysteamine.
胱氨酸贮积症是一种常染色体隐性溶酶体贮积病,由CTNS基因突变引起。最常见的CTNS突变是一个57 kb的缺失,在美国和北欧约60%的患者中出现,该突变缺失了外显子1 - 9、外显子10的大部分、CTNS启动子区域以及一个功能未知的相邻基因CARKL的全部。CTNS编码溶酶体胱氨酸转运蛋白,其缺失导致细胞内胱氨酸积累、广泛的细胞破坏、婴儿期的肾范科尼综合征、儿童后期的肾小球肾衰竭以及其他全身并发症。由于口服半胱胺治疗可显著预防或延迟这些并发症,因此早期准确诊断至关重要。本研究描述了用于CTNS中57 kb缺失的荧光原位杂交(FISH)探针的产生,使细胞遗传学实验室能够检测这种常见突变。这些探针还能够检测频率较低的11.7 kb缺失。使用多重PCR分析作为金标准进行了一项盲法研究,以确定57 kb缺失的存在与否。在来自单缺失、双缺失和未缺失患者的12个淋巴母细胞系上评估的FISH探针,在每种情况下都做出了正确诊断。这似乎是首次描述的针对任何溶酶体贮积病的基于FISH的诊断方法。它可以协助胱氨酸贮积症的产前和围产期诊断,并促进更早地使用半胱胺进行有益治疗。