Is hypothyroidism genetic?

Hypothyroidism is the most common thyroid disorder, affecting more than one million people in Spain, and most may not even know they have it. This metabolic disorder shows nonspecific symptoms, making it difficult to distinguish from other pathologies [1]. In the general population, hypothyroidism has a prevalence of 1.4 percent in adult women and 0.1 percent in men.

 

Thyroid malfunction has multiple health implications. Thyroid disorders are quite common and, if not diagnosed or treated early, can worsen. In addition, they are risk factors for other diseases such as heart conditions, diabetes, hypertension, etc [2].

 

What is hypothyroidism?

 

The thyroid is a butterfly-shaped gland located in the front of the neck, above the collarbone. Its main function is to produce thyroid hormones [4]. Hypothyroidism (underactive thyroid) is a disorder in which the thyroid gland, or thyroid, does not produce enough of certain crucial hormones: thyroid hormones [3].

 

The hormones produced by the thyroid, triiodothyronine (T3) and thyroxine (T4), have a major impact on health. They affect all aspects of metabolism and influence the control of vital functions such as regulation of body temperature and heart rate [3].

 

Causes of hypothyroidism

 

There are different causes that could lead to hypothyroidism. For example, autoimmune disorders. An autoimmune disorder or disease is one in which the body does not recognize a certain part of the body as its own and attacks it with antibodies. This is the case of Hashimoto’s thyroiditis, in which the immune system attacks the thyroid causing hypothyroidism [5, 6]. 

 

Other causes of the development of hypothyroidism include the following: 

 

– Thyroiditis or inflammation of the thyroid. 

– Thyroid surgery.

– Radiation therapy.

– Certain medications.

– Genetic factors. 

 

And, less frequently [3]:

 

– Congenital hypothyroidism.

– Disorders of the pituitary gland.

– Pregnancy

– Iodine deficiency

 

Diet for hypothyroidism

 

It could be said that there is no specific diet for hypothyroidism. There is no scientific evidence that eating or avoiding certain foods improves thyroid function in people with hypothyroidism. However, there are some known foods that can promote normal thyroid function, such as iodine.

 

In developed countries iodine is found as an additive in salt and many foods, so the disease derived from this deficiency is practically extinct. With a balanced diet it would not even be necessary to take iodine supplements. In any case, avoiding extremes in the diet will preserve thyroid health [7].

 

If you suffer from hypothyroidism, you have to keep in mind that the intake of thyroid hormone replacement medication should be done as directed by the specialist, usually on an empty stomach. It is important to know that too much fiber in the diet can prevent the correct absorption of the medication for the disease. Although there are no medications prohibited in hypothyroidism, there are some that can have the same effect as fiber. For example, it would be necessary to distance the intake of medication from the intake of these products [7]:

 

• Nuts
• Soybean meal
• Cottonseed meal
• Iron supplements or multivitamins containing iron
• Calcium supplements
• Antacids containing aluminum, magnesium, or calcium
• Some ulcer medications, such as sucralfate
• Some cholesterol-lowering medications, such as those containing cholestyramine and colestipol 

 

Is hypothyroidism genetic?

 

Even though hypothyroidism is not entirely genetic, as it’s usually explained by various factors, some of its types have both genetic and environmental causes. This is the case, for example, of congenital hypothyroidism, which occurs when the thyroid does not produce normal amounts of hormones at birth, or even before. Generally, the birth of babies with problems in the production of thyroid hormones is usually of hereditary origin. Although there are also cases of babies who develop congenital hypothyroidism because the pituitary gland does not produce enough TSH or because the thyroid gland cannot respond to TSH [8].

 

In addition, recent GWAS-type genetic studies (which look for genome-wide markers related to a disease), show that there are some genes that appear to be risk factors for the development of hypothyroidism, such as the family of genes known as the human leukocyte antigen (HLA) complex, which helps the immune system distinguish its own proteins from those produced by viruses, bacteria, and other agents. Other genes that have been described as being related to hypothyroidism include the INSR, PDE8B and VAV3 genes, among others. The great diversity of genes described in association with this disease is indicative of great heterogeneity in the genetic etiology of hypothyroidism[9].

 

24Genetics and hypothyroidism

 

Thanks to the 24Genetics health test you can know what genetic predisposition you have to suffer hypothyroidism through the analysis of genes involved in its causes. Ask us any questions you have about it and our experts will solve them without obligation.

 

Bibliography

 

[1] More than one million people in Spain have hypothyroidism. Actualidad Sanitaria published May. 2021; accessed Nov. 2022] Available at: https://actualidadsanitaria.com/enfermedades/mas-de-un-millon-de-personas-en-espana-tienen-hipotiroidismo/ 

 

[2] Estimation of the prevalence of hypothyroidism in Castilla y León and its evolution from 1992 to 2000 through the consumption of thyroid hormones. Rev. Esp. Salud Publica vol.75 no.4 – Alfonso Díaz Madero and Adela López Ferreras [published Jul./Aug. 2001; accessed Nov. 2022] Available at: https://scielo.isciii.es/scielo.php?script=sci_arttext&pid=S1135-57272001000400008#:~:text=La%20prevalencia%20del%20hipotiroidismo%20en%20la%20poblci%20poblci%20C3%B3n%20general%20es%20del,un%206%25%20en%20mujeres1. 

 

[3] Hypothyroidism (underactive thyroid). Mayo Clinic [published Nov. 2020; accessed Nov. 2022] Available from: https://www.mayoclinic.org/es-es/diseases-conditions/hypothyroidism/symptoms-causes/syc-20350284. 

 

[4] MedlinePlus in Spanish [Internet]. Thyroid diseases [accessed Nov. 2022]; Available from: https://medlineplus.gov/spanish/thyroiddiseases.html#:~:text=The%20problems%20thyroid%20include%3A,does%20not%20produce%20sufficient%20thyroid%20hormone. 

 

[5] MedlinePlus in Spanish [Internet]. Hypothyroidism [accessed Nov. 2022]; Available from: https://medlineplus.gov/spanish/hypothyroidism.html 

 

[6] Hypothyroidism. Clínica Universidad de Navarra – Dr. Juan Carlos Galofré Ferrater [accessed Nov. 2022] Available from: https://www.cun.es/enfermedades-tratamientos/enfermedades/hipotiroidismo 

 

[7] Diet to treat hypothyroidism: Can certain foods increase thyroid function? Mayo Clinic – Ann Kearns, M.D [published Dec. 2019; accessed Nov. 2022] Available at: https://www.mayoclinic.org/es-es/diseases-conditions/hypothyroidism/expert-answers/hypothyroidism-diet/faq-20058554 

 

[8] Information for understanding what congenital hypothyroidism is. Mass General Brigham for Children [published Apr. 2015; accessed Nov. 2022] Available from: https://www.massgeneral.org/children/hypothyroidism/informacion-para-comprender-que-es-el-hipotiroidismo-congenito 

 

[9] Eriksson N, Tung JY, Kiefer AK, Hinds DA, Francke U, Mountain JL, Do CB. Novel associations for hypothyroidism include known autoimmune risk loci. PLoS One. 2012;7(4):e34442. doi: 10.1371/journal.pone.0034442. Epub 2012 Apr 6. PMID: 22493691; PMCID: PMC3321023