The Laboratory of Clinical Genetics, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China.
Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China.
Hum Genomics. 2024 Nov 28;18(1):133. doi: 10.1186/s40246-024-00697-3.
The clinical diagnosis of Fabry Disease (FD) can be challenging due to the clinical heterogeneity, especially in females. Patients with FD often experience a prolonged interval between the onset of symptoms and receiving a diagnosis. Genetic testing is the gold standard for precise diagnosis of FD, however conventional genetic testing could miss deep intronic variants and large deletions or duplications. Although next-generation sequencing, which analyzes numerous genes, has been successfully used for FD diagnosis and can detect complex variants, an effective and rapid tool for identifying a wide range of variants is imminent, contributing to decrease the diagnostic delay.
The comprehensive Analysis of FD (CAFD) assay was developed for FD genetic diagnosis, employing long-range PCR coupled with long-read sequencing to target the full-length GLA gene and its flanking regions. Its clinical performance was assessed through a comparative analysis with Sanger sequencing.
Genetic testing was performed on 82 individuals, including 48 probands and 34 relatives. The CAFD assay additionally identified variants in two probands: one had a novel and de novo pathogenic variant with a 1715 bp insertion in intron 4, and the other carried two deep intronic VUS variants in cis-configuration also in intron 4. In total, CAFD identified 47 different variants among 48 probands. Of these, 42 (89.36%, 42/47) were pathogenic, while 5 (10.64%, 5/47) were VUS. Sixteen (34.04%, 16/47) of the variants were novel, including 15 SNV/Indels and one large intronic insertion. Pedigree analysis of 21 probands identified four de novo disease-causing variants. Hence, FD exhibits not only variable clinical presentations but also a wide spectrum of variants. Utilizing a comprehensive testing algorithm for diagnosing FD, which includes enzyme activity, clinical features, and genetic testing, the diagnostic yield of CAFD is 97.92% (47/48), which is higher than that of conventional Sanger sequencing, at 95.83% (46/48).
The duration between initial clinical presentation and diagnosis remains long and winding. CAFD provides precise diagnosis for a wide spectrum of GLA variants, promoting timely diagnosis and appropriate treatment for FD patients.
由于临床表现的异质性，尤其是在女性中，法布里病（Fabry Disease，FD）的临床诊断颇具挑战性。FD 患者在出现症状与获得诊断之间往往存在较长的时间间隔。基因检测是 FD 精确诊断的金标准，但传统的基因检测可能会遗漏深度内含子变异和大片段缺失或重复。尽管分析众多基因的下一代测序已成功用于 FD 诊断，并且可以检测复杂变异，但仍迫切需要一种有效的、快速的工具来识别广泛的变异，有助于缩短诊断延迟。
采用长片段 PCR 结合长读测序靶向全长 GLA 基因及其侧翼区域，开发了用于 FD 基因诊断的全面分析 FD（CAFD）检测。通过与 Sanger 测序的比较分析，评估其临床性能。
对 82 名个体进行了基因检测，包括 48 名先证者和 34 名亲属。CAFD 检测还在 2 名先证者中鉴定出了变异：一名先证者携带 4 号内含子中 1715bp 的新的从头致病性插入，另一名先证者携带两个 cis 构型的深度内含子 VUS 变异。在 48 名先证者中，CAFD 共鉴定出 47 种不同的变异。其中，42 种（89.36%，42/47）为致病性变异，5 种（10.64%，5/47）为意义未明变异。16 种（34.04%，16/47）为新变异，包括 15 种 SNV/Indels 和 1 种大片段内含子插入。21 名先证者的家系分析发现了 4 种新的致病性变异。因此，FD 不仅表现出不同的临床表现，而且还具有广泛的变异谱。通过使用包括酶活性、临床特征和基因检测在内的综合 FD 诊断检测算法，CAFD 的诊断率为 97.92%（47/48），高于传统 Sanger 测序的 95.83%（46/48）。
从初始临床表现到诊断的时间仍然漫长而曲折。CAFD 为广泛的 GLA 变异提供了精确诊断，促进了 FD 患者的及时诊断和适当治疗。
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