Abstract：
Familial Hypophosphatasia presents a complex diagnostic challenge due to its wide-ranging clinical manifestations and genetic heterogeneity. This study aims to elucidate the molecular underpinnings of familial Hypophosphatasia within a Tunisian family harboring a rare c.896 T > C mutation in the ALPL gene, offering insights into genotype-phenotype correlations and potential therapeutic avenues. The study employs a comprehensive approach, integrating biochemical examination, genetic analysis, structural modeling, and functional insights to unravel the impact of this rare mutation. Genetic investigation revealed the presence of the p.Leu299Pro mutation within the ALPL gene in affected family members. This mutation is strategically positioned in proximity to both the catalytic site and the metal-binding domain, suggesting potential functional consequences. Homology modeling techniques were employed to predict the 3D structure of TNSALP, providing insights into the structural context of the mutation. Our findings suggest that the mutation may induce conformational changes in the vicinity of the catalytic site and metal-binding domain, potentially affecting substrate recognition and catalytic efficiency. Molecular dynamics simulations were instrumental in elucidating the dynamic behavior of the tissue-nonspecific alkaline phosphatase isozyme (TNSALP) in the presence of the p.Leu299Pro mutation. The simulations indicated alterations in structural flexibility near the mutation site, with potential ramifications for the enzyme\'s overall stability and function. These dynamic changes may influence the catalytic efficiency of TNSALP, shedding light on the molecular underpinnings of the observed clinical manifestations within the Tunisian family. The clinical presentation of affected individuals highlighted significant phenotypic heterogeneity, underscoring the complex genotype-phenotype correlations in familial Hypophosphatasia. Variability in age of onset, severity of symptoms, and radiographic features was observed, emphasizing the need for a nuanced understanding of the clinical spectrum associated with the p.Leu299Pro mutation. This study advances our understanding of familial Hypophosphatasia by delineating the molecular consequences of the p.Leu299Pro mutation in the ALPL gene. By integrating genetic, structural, and clinical analyses, we provide insights into disease pathogenesis and lay the groundwork for personalized therapeutic strategies tailored to specific genetic profiles. Our findings underscore the importance of comprehensive genetic and clinical evaluation in guiding precision medicine approaches for familial Hypophosphatasia.
摘要：
家族性低磷酸盐血症由于其广泛的临床表现和遗传异质性而提出了复杂的诊断挑战。这项研究旨在阐明在ALPL基因中具有罕见的c.896T>C突变的突尼斯家族中家族性低磷酸盐症的分子基础，提供对基因型-表型相关性和潜在治疗途径的见解。这项研究采用了全面的方法，综合生化检查，遗传分析,结构建模,和功能性见解来解开这种罕见突变的影响。遗传调查显示，在受影响的家庭成员中，ALPL基因中存在p.Leu299Pro突变。该突变策略性地位于催化位点和金属结合结构域附近,暗示潜在的功能后果。同源性建模技术用于预测TNSALP的3D结构，提供对突变的结构背景的见解。我们的发现表明，突变可能会引起催化位点和金属结合域附近的构象变化，可能影响底物识别和催化效率。分子动力学模拟有助于阐明在p.Leu299Pro突变存在下组织非特异性碱性磷酸酶同工酶（TNSALP）的动态行为。模拟表明突变位点附近的结构灵活性发生了变化，对酶的整体稳定性和功能有潜在的影响。这些动态变化可能会影响TNSALP的催化效率，揭示了突尼斯家族中观察到的临床表现的分子基础。受影响个体的临床表现突出了显著的表型异质性，强调家族性低磷酸盐症复杂的基因型-表型相关性。发病年龄的变异性，症状的严重程度，并观察到射线照相特征，强调需要对与p.Leu299Pro突变相关的临床谱进行细致的理解。这项研究通过描述ALPL基因中p.Leu299Pro突变的分子后果，促进了我们对家族性低磷酸盐症的理解。通过整合遗传，结构,和临床分析，我们提供了对疾病发病机制的见解,并为针对特定基因谱的个性化治疗策略奠定了基础.我们的发现强调了全面的遗传和临床评估在指导家族性低磷酸盐症的精准医学方法中的重要性。
