Functional study of three cases with novel TBX19 variants.

IF 3.7 3区医学 Q2 Medicine

Endocrine Pub Date : 2025-01-08 DOI:10.1007/s12020-024-04153-z

NokI Lei, Xiang Qiu, Wunying Li, Yanlin Liu, Ronggui Hu, Chuanyin Li, Wenli Lu

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引用次数: 0

Abstract

Purpose: Congenital isolated adrenocorticotropic hormone deficiency (CIAD) is an autosomal recessive disorder. This study identifies novel TBX19 variants for CIAD patients, explores its possible effect mechanism at the structural, functional and protein levels, and guides clinicians better understand the condition.

Methods: The clinical characteristics of three CIAD children were summarized. Multiple sequence alignment was performed and five algorithms, PROVEA, PolyPhen2, Mutation Taster, FATHMM, and I Mutant2.0, were used for the pathogenicity prediction. In addition, the three-dimensional protein structure of wild-type TBX19 was generated by Alphafold 3 and its variants were shown using PyMOL. Furthermore, immunoblotting analysis was applied to examine changes in the protein levels and the luciferase reporter assay was performed to further investigate the effects of TBX19 and its variants on pro-opiomelanocortin (POMC) transcriptional activity.

Results: We describe three Chinese patients with CIAD caused by TBX19 variants. The TBX19 variant, c.856C>T (p.R286*) was classified as pathogenic according to ACMG, whereas the other four variants, c.377C>T (p.P126L), c.602A>T (p.E201V), c.401A>G (p.H134R) and c.299G>A (p.R100H) were predicted to be disease-causing. Variants lead to alter interactions, conformational changes in proteins or truncate protein. TBX19 and PITX1 cooperated, resulting in a strong synergistic activation effect on POMC transcriptional expression. A functional study showed that the variants in our study result in a significant suppression of POMC transcriptional activity compared to wild-type TBX19.

Conclusions: Our study identifies five TBX19 loss-of-function variants, two of which are novel and that provides new perspectives into the pathophysiological mechanism and expands the variant spectrum in IAD.

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3例新型TBX19变异的功能研究。

目的：先天性孤立性促肾上腺皮质激素缺乏症是一种常染色体隐性遗传病。本研究确定了CIAD患者的新型TBX19变异，从结构、功能和蛋白水平探讨其可能的作用机制，指导临床医生更好地了解病情。方法：总结3例CIAD患儿的临床特点。采用PROVEA、PolyPhen2、Mutation Taster、FATHMM和I Mutant2.0 5种算法进行致病性预测。此外，使用Alphafold 3生成野生型TBX19的三维蛋白结构，并使用PyMOL显示其变体。此外，采用免疫印迹法检测蛋白水平的变化，并采用荧光素酶报告基因法进一步研究TBX19及其变体对前阿皮黑色素皮质素（POMC）转录活性的影响。结果：我们描述了3例由TBX19变异引起的CIAD患者。根据ACMG预测，TBX19的c.856C>T （p.R286*）具有致病性，c.377C>T （p.P126L）、c.602A>T （p.E201V）、c.401A b> G （p.p h134r）和c.299G>A （p.R100H）具有致病性。变异导致蛋白质相互作用的改变、构象的改变或截断蛋白质。TBX19与PITX1协同作用，对POMC转录表达产生较强的协同激活作用。功能研究表明，与野生型TBX19相比，我们研究中的变体导致POMC转录活性显著抑制。结论：我们的研究确定了5个TBX19功能丧失变异，其中两个是新的，为IAD的病理生理机制提供了新的视角，并扩展了变异谱。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Endocrine 医学-内分泌学与代谢

CiteScore

6.40

自引率

5.40%

发文量

期刊介绍： Well-established as a major journal in today’s rapidly advancing experimental and clinical research areas, Endocrine publishes original articles devoted to basic (including molecular, cellular and physiological studies), translational and clinical research in all the different fields of endocrinology and metabolism. Articles will be accepted based on peer-reviews, priority, and editorial decision. Invited reviews, mini-reviews and viewpoints on relevant pathophysiological and clinical topics, as well as Editorials on articles appearing in the Journal, are published. Unsolicited Editorials will be evaluated by the editorial team. Outcomes of scientific meetings, as well as guidelines and position statements, may be submitted. The Journal also considers special feature articles in the field of endocrine genetics and epigenetics, as well as articles devoted to novel methods and techniques in endocrinology. Endocrine covers controversial, clinical endocrine issues. Meta-analyses on endocrine and metabolic topics are also accepted. Descriptions of single clinical cases and/or small patients studies are not published unless of exceptional interest. However, reports of novel imaging studies and endocrine side effects in single patients may be considered. Research letters and letters to the editor related or unrelated to recently published articles can be submitted. Endocrine covers leading topics in endocrinology such as neuroendocrinology, pituitary and hypothalamic peptides, thyroid physiological and clinical aspects, bone and mineral metabolism and osteoporosis, obesity, lipid and energy metabolism and food intake control, insulin, Type 1 and Type 2 diabetes, hormones of male and female reproduction, adrenal diseases pediatric and geriatric endocrinology, endocrine hypertension and endocrine oncology.