Article Text
Abstract
Background In several countries, thyroid dyshormonogenesis is more common than thyroid dysgenesis in patients with congenital hypothyroidism (CH). However, known pathogenic genes are limited to those directly involved in hormone biosynthesis. The aetiology and pathogenesis of thyroid dyshormonogenesis remain unknown in many patients.
Methods To identify additional candidate pathogenetic genes, we performed next-generation sequencing in 538 patients with CH and then confirmed the functions of the identified genes in vitro using HEK293T and Nthy-ori 3.1 cells, and in vivo using zebrafish and mouse model organisms.
Results We identified one pathogenic MAML2 variant and two pathogenic MAMLD1 variants that downregulated canonical Notch signalling in three patients with CH. Zebrafish and mice treated with N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butylester, a γ-secretase inhibitor exhibited clinical manifestations of hypothyroidism and thyroid dyshormonogenesis. Through organoid culture of primary mouse thyroid cells and transcriptome sequencing, we demonstrated that Notch signalling within thyroid cells directly affects thyroid hormone biosynthesis rather than follicular formation. Additionally, these three variants blocked the expression of genes associated with thyroid hormone biosynthesis, which was restored by HES1 expression. The MAML2 variant exerted a dominant-negative effect on both the canonical pathway and thyroid hormone biosynthesis. MAMLD1 also regulated hormone biosynthesis through the expression of HES3, the target gene of the non-canonical pathway.
Conclusions This study identified three mastermind-like family gene variants in CH and revealed that both canonical and non-canonical Notch signalling affected thyroid hormone biosynthesis.
- congenital, hereditary, and neonatal diseases and abnormalities
- endocrine system diseases
- genetics, medical
Data availability statement
Data are available on reasonable request.
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- congenital, hereditary, and neonatal diseases and abnormalities
- endocrine system diseases
- genetics, medical
Data availability statement
Data are available on reasonable request.
Footnotes
F-YW, R-MY, H-YZ and MZ are joint first authors.
H-DS, FC and S-XZ contributed equally.
Contributors F-YW designed the study, conducted the statistical analysis and drafted the manuscript. R-MY designed the study and revised the manuscript. H-YZ and MZ conducted the statistical analysis. FC, P-HT, C-XZ, S-YS, MD, R-JC, X-YL, FS, R-JZ, C-YY, ZW, LY and JL collected the clinical data of patients. HS and S-XZ guided the design of the study and revised the manuscript. S-XZ acts as a guarantor.
Funding This work was supported by grants from National Science Foundation of China (numbers 82070816, 81870537, 82170802), Shanghai Municipal Education Commission Two-hundred Talent (number 20161318), Shanghai Science and Technology Committee (number 19140904200), Innovative Research Team of High-Level Local Universities in Shanghai (SHSMU-ZDCX20210901, SHSMU-ZDCX20212501).
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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