Novel Dried Blood Spot Mass Spectrometry Functional Assays for Lysosomal Acid Lipase and N-acetylgalactosamine-sulfate Sulfatases for Use in Newborn Screening

用于新生儿筛查的溶酶体酸性脂肪酶和 N-乙酰半乳糖胺硫酸酯硫酸酯酶的新型干血斑质谱功能分析

• 批准号: 9238498
• 负责人: Sophia Masi
• 金额: $ 4.9万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-16 至 2019-09-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9238498
• 关键词: Acetylgalactosamine; Acid Lipase; Affect; Atherosclerosis; Biological Assay; Blood; Cessation of life; Child; Cholesterol; Cholesterol Ester Storage Disease; Cholesterol Esters; Cleaved cell; Clinical; Connective Tissue; Coupling; Daughter; Defect; Development; Diagnosis; Diagnostic tests; Disease; Eligibility Determination; Enzymes; Esters; GALNS gene; Galactosamine; Glycosaminoglycans; Health; Human; Hydrolysis; Incidence; Infant; Intervention; Ions; Leukocytes; Life; Lysosomal Storage Diseases; Mass Spectrum Analysis; Metabolism; Mucopolysaccharidoses; Mucopolysaccharidosis IV A; Mucopolysaccharidosis VI; Neonatal Screening; Outcome; Pathway interactions; Patients; Phase III Clinical Trials; Protocols documentation; Rare Diseases; Savings; Scanning; Serum; Source; Spottings; Sulfatases; Supportive care; Transportation; Triglycerides; Unspecified or Sulfate Ion Sulfates; Wolman Disease; cost; design; diagnostic assay; emerging adult; enzyme activity; enzyme replacement therapy; improved; inhibitor/antagonist; liver function; novel; public health relevance; screening; skeletal tissue; tandem mass spectrometry

 DESCRIPTION (provided by applicant): Defects in the human cholesterol transportation pathway can create two ultimately fatal recessive diseases (Wolman's disease and Cholesterol Ester Storage disease or CESD). The responsible enzyme, lysosomal acid lipase or LAL, is unable carry out its cholesterol ester hydrolysis function, resulting in a severe decline in liver function for Wolman's disease patients and a rapid increase in both cholesterol and triglyceride levels in blood serum with increased incidence of atherosclerotic disease in CESD patients' vessels by early adulthood. Yet, no recommended or universal diagnostic assay exists for either of these two diseases, resulting in many missed cases. By using a specific LAL substrate or an existing irreversible inhibitor of LAL, we will be able to specifically assay LAL enzymatic activit in dried blood spots. Likewise, the development of a more sensitive DBS assay for the more rare mucopolysaccharidoses (MPS) types IVA and VI will greatly benefit screening and diagnosing deficiencies due to the low baseline activity of these enzymes. The use of dried blood spots (DBS) is a low cost, relatively long-lived source of the enzymes found in leukocytes. Mass spectrometry will serve to quantify the amount of cleaved substrate from daughter ion fragmentation (or MS/MS scans), providing a high sensitivity for even small changes in enzyme function, which is critical for minimizing false positives in clinical settings. The development of an MS/MS dried blood spot assay for LAL deficiencies as well as improved MPS IVA and VI MS/MS DBS assays will provide newborn screening centers a means to efficiently identify potential cases that require immediate intervention and potentially life-long therapy that will protect the lives of these affected children.

 描述（由申请人提供）：人类胆固醇转运途径的缺陷可导致两种最终致命的隐性疾病（Wolman病和胆固醇酯储存病或CESD）。负责的酶，溶酶体酸性脂肪酶或LAL，不能进行其胆固醇酯水解功能，导致Wolman病患者肝功能严重下降，血清中胆固醇和甘油三酯水平快速增加，CESD患者血管中动脉粥样硬化疾病的发病率在成年早期增加。然而，对于这两种疾病中的任何一种，都没有推荐或通用的诊断方法，导致许多病例被遗漏。通过使用特定的LAL底物或现有的LAL不可逆抑制剂，我们将能够在干血斑中特异性测定LAL酶活性。同样地，开发用于更罕见的粘多糖（MPS）IVA和VI型的更灵敏的DBS测定将极大地有利于筛查和诊断由于这些酶的低基线活性而导致的缺陷。干血斑（DBS）的使用是白细胞中发现的酶的低成本、相对长寿命的来源。质谱法将用于量化来自子离子碎片化（或MS/MS扫描）的裂解底物的量，从而为酶功能中的甚至微小变化提供高灵敏度，这对于最小化临床环境中的假阳性是至关重要的。的发展 用于LAL缺陷的MS/MS干血斑测定以及改进的MPS IVA和VI MS/MS DBS测定将为新生儿筛查中心提供一种有效识别需要立即干预和潜在终身治疗的潜在病例的方法，这将保护这些受影响儿童的生命。