|LETTER TO THE EDITOR
|Year : 2016 | Volume
| Issue : 2 | Page : 94-95
Thyroid ectopia is distinctly uncommon in Indian children with permanent congenital hypothyroidism due to dysgenetic glands
Department of Pediatrics, Pediatric Endocrinology and Diabetes Unit, Advanced Pediatric Center, Post Graduate Institute of Medical Education and Research, Chandigarh, India
|Date of Web Publication||1-Jun-2016|
Dr. Devi Dayal
Department of Pediatrics, Pediatric Endocrinology and Diabetes Unit, Advanced Pediatric Center, Post Graduate Institute of Medical Education and Research, Chandigarh - 160 012
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Dayal D. Thyroid ectopia is distinctly uncommon in Indian children with permanent congenital hypothyroidism due to dysgenetic glands. Thyroid Res Pract 2016;13:94-5
|How to cite this URL:|
Dayal D. Thyroid ectopia is distinctly uncommon in Indian children with permanent congenital hypothyroidism due to dysgenetic glands. Thyroid Res Pract [serial online] 2016 [cited 2020 Aug 7];13:94-5. Available from: http://www.thetrp.net/text.asp?2016/13/2/94/183276
The recent article by Patil et al. made for an interesting read. Their case series on ectopic thyroid gland (ETG) is an important addition to the scarce Indian literature on morphological spectrum of thyroid dysgenesis (TD), the most common cause of permanent congenital hypothyroidism (CH). A significant point of the study is the use of more than a single imaging modality for the characterization of ETG in majority of the patients. As mentioned in their article, the frequency of ETG has increased due to improved detection by the now available advanced diagnostic techniques such as high-resolution ultrasonography and thyroid scintigraphy. However, the overall prevalence of ETG as a part of TD is extremely low in Indian patients as compared to the global scenario. Worldwide, ETG is considered to be the most common form of TD with a prevalence of about 1:100,000–300,000 persons and 1:4000–8000 patients with thyroid disease., In the current series, ETG during childhood (<12 years) was diagnosed in nine patients over a period of 9 years, although the proportion of other variants of TD in the cohort is not mentioned. This frequency is similar to our recently published data over a similar time frame. In 94 children (<12 years) with TD, we diagnosed ETG in only 14 (14.8%); the rest had either agenesis (74, 78.7%) or hypoplasia (6, 6.4%). Both these studies suggest a low prevalence of ETG as a variant of TD in Indian patients with permanent CH. The findings are similar to the two recent studies from Turkey and Iran , but in sharp contrast to studies from rest of the world.,
At present, the causes for such a different etiological spectrum of TD in Indian patients are unknown but are probably related to genetic heterogeneity of the disease in different patient populations. Although genetic mutations associated with TD are detected in <5% of all cases, the candidate genes probably determine the TD form. It is possible that the frequency of mutations in genes for certain thyroid transcription factors considered as candidate genes for ETG (PAX8, NKX2-1, FOXE1, and PAX9) is lower in Indian patients. This question can only be answered by large worldwide genetic studies in patients with TD. A female preponderance noted in the present study, as well as in some previous studies, may also suggest a role of sexual dimorphism in ETG. In this context, large multicenter studies are needed to first characterize and document the true prevalence of different TD variants in our country and second, to identify the factors responsible for the different etiological spectrum as compared to the data on TD from other regions of the world.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Patil M, Ayyar V, Bantwal G, Raman A, George B, Mathew V. Thyroid ectopia: A case series and literature review. Thyroid Res Pract 2015;12:110-15. DOI: 10.4103/0973-0354.157917 [Last cited on 2015 Aug 04].
Dayal D, Prasad R. Congenital hypothyroidism: Current perspectives. Res Rep Endocr Disord 2015;5:91-102.
Bekhit OE, Yousef RM. Permanent and transient congenital hypothyroidism in Fayoum, Egypt: A descriptive retrospective study. PLoS One 2013;8:e68048.
Dayal D, Sindhuja L, Bhattacharya A, Sodhi KS, Sachdeva N. Agenesis and not ectopia is common in North Indian children with thyroid dysgenesis. Indian J Endocrinol Metab 2014;18 Suppl 1:S97-9.
Kirmizibekmez H, Güven A, Yildiz M, Cebeci AN, Dursun F. Developmental defects of the thyroid gland: Relationship with advanced maternal age. J Clin Res Pediatr Endocrinol 2012;4:72-5.
Hashemipour M, Ghasemi M, Hovsepian S, Heiydari K, Sajadi A, Hadian R, et al.
Etiology of congenital hypothyroidism in Isfahan: Does it different? Adv Biomed Res 2014;3:21.