Home » Quick and Important Facts on Genetic Link of Hypothyroidism

Quick and Important Facts on Genetic Link of Hypothyroidism

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Hypothyroidism is a medical condition that involves the insufficient production of thyroid hormones, and there are studies showing that hypothyroidism genetic link plays an important role in hormonal therapy.

As you probably know, thyroid hormone is used to run the metabolism of the body, and hypothyroidism is associated with slow metabolism.

In fact, 10 percent of women have some degree of thyroid hormone deficiency, and an estimate of 10 million Americans have hypothyroidism.

What Are the Causes of Hypothyroidism?

  1. Inflammation of the thyroid gland

A history or current inflammation of the thyroid gland causes damage to the thyroid gland cells. If these cells are damaged, they won’t be able to produce enough hormones to be used for proper metabolism.

Hashimoto’s thyroiditis is an example of autoimmune thyroiditis or inflammation of the thyroid gland caused by the patient’s own immune system, which somehow shows a hypothyroidism genetic link.

  1. Medical treatments

If the thyroid gland is removed due to inflammation or due to the presence of a nodule or tumor, the remaining thyroid-producing cells are not sufficient to meet the body’s needs. This will result in hypothyroidism, and the patient needs to take thyroid hormone for life.

Medical treatments are now being studied and discovered with hypothyroidism genetic link playing an important role in choosing the best intervention for hypothyroidism.

  1. Genetic link or congenital hypothyroidism

This involves the partial or complete loss of thyroid gland function. It affects infants because of either intrauterine factor or genetic link.

What Is the Role of Genetics?

In most cases, congenital hypothyroidism is sporadic, and it occurs without history in the family. However, genes also play a big role if autosomal recessive inheritance disorder is involved. This condition results in both of the gene copies in each cell to mutate.

The parents with autosomal recessive condition carry a single copy of the mutated gene, and they don’t manifest the signs and symptoms of hypothyroidism.

The mutations of genes cause alterations, affecting the formation of cells in the early embryonic development.

These mutations happen with TSHR gene, PAX8 gene, or DUOX2 gene. Thyroid-stimulating hormone receptor or TSHR attaches itself to the thyroid-stimulating hormone or TSH.

It helps in producing iodine-containing hormones, helping in the regulation of growth, metabolism, and brain development.

Hypothyroidism Genetics and Treatment Study

You might wonder what studies and research show linking hypothyroidism with heredity.

According to Dr. Allan Carle of the Department of Endocrinology of Aalborg University Hospital in Denmark, the presence of common genetic variant predicts why there are patients with hypothyroidism who need treatment using T3 and T4.

He shared in the 2016 Annual Meeting of the American Thyroid Association that 50 percent of patients prefer a combined treatment of T3 and T4 instead of T4 only. There are patients benefiting from these therapies, but there are some who do not.

Dr. Carle, together with his colleagues, aims to identify the role of deiodinase or DIO2 in the transport-facilitating monocarboxylate transporter or MCT10 genes of the cellular membrane, regulating thyroid hormones’ intracerebral availability.

In this study, 45 subjects with previous hypothyroidism achieved euthyroidism within 6 months and some even more on standard or traditional T4 therapy.

This only proves a hypothyroidism genetic link.

What Are the Findings of Combined Therapy?

About 50 percent of patients in a double-blind crossover study were randomized. They underwent a continuous T4 therapy for 3 consecutive months followed by T4–T3 therapy combined for 3 months. In both cases, a T4 dose of 50 mg was replaced by either identical T4 (50 mg) or T3 (20 mg).

About 60 percent of patients with a polymorphism in their genes preferred the combined T4–T3 therapy.

According to these findings, the use of T4 combined with T3 therapy is more effective for inherited hypothyroidism. At the very least, testing should be done to find out a genetic hint or molecular basis before choosing the best treatment for patients suffering from hypothyroidism.

This hypothyroidism genetic link is important in the study and discovery of new treatments for hypothyroidism.

Study Supported

The study of Dr. Carle and his colleagues is supported by the John Hopkins University School of Medicine, headed by Dr. Michael Mingzhao Xing.

Dr. Xing has no direct relationship with Dr. Carle, but is a professor of oncology, pathology, and general medicine in the Division of Endocrinology at John Hopkins.

This shows that gene testing is required to ensure the effectiveness of combined therapies.

Hereditary Influences of Thyroid Hormones in Twins

A study done in the UK showed that the environmental and genetic factors are associated with the blood concentration levels of free T3, free T4, TSH, and the free T4 x TSH product and variation. The subjects of the study included female monozygous and dizygous twins in 213 and 849 pairs respectively, all coming from the TwinsUK registry.

The median age is 45 years old, and the age range is between 18 and 80 years old. The study shows that genetic regulation is a significant determinant of the free T4 x TSH and TSH. However, it is a less important determinant when it comes to the free T4 and free T3 levels among Caucasian women.

Environmental factors play a crucial role in less explained science of genetics. It only goes to show that the hypothyroidism genetic link needs further studies and analysis.


Hypothyroidism can be associated with genetics or environmental factors.

It is important to learn about the role of genes in the occurrence of hypothyroidism to be able to determine the right treatment needed. Indeed, there is a proven study of hypothyroidism genetic link for a more effective treatment.

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