Cretinism pathophysiology
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:
Overview
The exact pathogenesis of [disease name] is not fully understood.
OR
It is thought that [disease name] is the result of / is mediated by / is produced by / is caused by either [hypothesis 1], [hypothesis 2], or [hypothesis 3].
OR
[Pathogen name] is usually transmitted via the [transmission route] route to the human host.
OR
Following transmission/ingestion, the [pathogen] uses the [entry site] to invade the [cell name] cell.
OR
[Disease or malignancy name] arises from [cell name]s, which are [cell type] cells that are normally involved in [function of cells].
OR
The progression to [disease name] usually involves the [molecular pathway].
OR
The pathophysiology of [disease/malignancy] depends on the histological subtype.
Pathophysiology
Pathogenesis
- It is thought that cretinism is caused by a congenital anomaly in the thyroid gland.
- Different mechanisms causing congenital hypothyroidism include the following:
- Thyroid dysgenesis:[1]
- Thyroid dysgenesis is the most common cause of congenital hypothyroidism. It is due to the absence of the thyroid gland, ectopic growth of the gland or the thyroid gland is hypoplastic.
- It is believed that thyroid dysgenesis is caused by a mutation in some genes responsible for thyroid formation and function. These genes include the following:
- Mutation in the TSH receptor is responsible for the hypoplastic thyroid gland.
- Mutations in the paired box 8 (PAX8) gene leads to thyroid dysgenesis.
- Mutations in the transcription factors NK2 homeobox 1, transcription factor-2, and NK2 homeobox 5 genes also lead to thyroid dysgenesis.
- Thyroid dyshormonogenesis:
- It is believed also that the defect in the synthesis of the thyroid hormone itself is another way of the pathogenesis of cretinism.
- The most common mechanism involved in decreasing thyroid hormone synthesis and secretion is the impairment of thyroid peroxidase enzyme. This impairment will lead to defect in the iodide oxidation and organification.
- Thyroid dysgenesis:[1]
Genetics
- Cretinism can occur due to genetic defects include the following: [2]
- Mutation in sodium-iodide symporter gene can impede the iodine transportation into the thyroid follicles. This mutation will decrease the synthesis of the thyroid hormone.[3]
Associated Conditions
- Cretinism may be associated with the following conditions: [4]
- Horseshoe kidney
- Ureterocele
- Undescended testes
- Hydrocele
- Cleft palate
- Bilateral choanal atresia
- Neurologic manifestations as ataxia
Gross Pathology
- There are no gross findings associated with cases of cretinism.
Microscopic Pathology
- On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
References
- ↑ Vilain C, Rydlewski C, Duprez L, Heinrichs C, Abramowicz M, Malvaux P; et al. (2001). "Autosomal dominant transmission of congenital thyroid hypoplasia due to loss-of-function mutation of PAX8". J Clin Endocrinol Metab. 86 (1): 234–8. doi:10.1210/jcem.86.1.7140. PMID 11232006.
- ↑ Gillam MP, Kopp P (2001). "Genetic defects in thyroid hormone synthesis". Curr Opin Pediatr. 13 (4): 364–72. PMID 11717564.
- ↑ Pohlenz J, Rosenthal IM, Weiss RE, Jhiang SM, Burant C, Refetoff S (1998). "Congenital hypothyroidism due to mutations in the sodium/iodide symporter. Identification of a nonsense mutation producing a downstream cryptic 3' splice site". J Clin Invest. 101 (5): 1028–35. doi:10.1172/JCI1504. PMC 508654. PMID 9486973.
- ↑ Carvalho A, Hermanns P, Rodrigues AL, Sousa I, Anselmo J, Bikker H; et al. (2013). "A new PAX8 mutation causing congenital hypothyroidism in three generations of a family is associated with abnormalities in the urogenital tract". Thyroid. 23 (9): 1074–8. doi:10.1089/thy.2012.0649. PMID 23647375.