About The Thyroid

The Thyroid can best be described as a tiny gland that is located below the skin and the muscles, in the front of the neck, at the area where people would generally have a bow tie. The thyroid itself is a brownish-red gland weighing less than an ounce. The gland has two lobes, or halves, and it somewhat resembles butterfly wings. This tiny gland helps the human body perform several vital bodily functions.

Our pediatric endocrinology specialists in Miami greatly understand the importance of this small gland and a condition called congenital hypothyroidism, which affects the thyroid and its functions from birth.

Is hypothyroidism genetic? What is congenital hypothyroidism, and can it be treated? In this article, our experts bring you the answers. 

About Hypothyroidism

Portrait of Little Girl Wearing Striped T-Shirt Touching Neck, Suffering Thyroid Disorder

Hypothyroidism is a condition caused by an underactive thyroid; more specifically, it’s a term used to describe the condition in which the thyroid gland fails to produce enough hormones that are responsible for triggering specific bodily functions. Low thyroid hormone levels may make the body use up energy at a slower rate, and the patient’s metabolism may slow down considerably. 

Having an underactive thyroid is a common condition, especially among adult women.

Congenital Hypothyroidism

Unfortunately, the condition may affect children as well. When hypothyroidism is diagnosed in a newborn, it is referred to as congenital hypothyroidism. 

Some children may develop the condition in their teens or in late childhood. In many cases, the culprit behind the underactive thyroid is Hashimoto’s thyroiditis, a type of autoimmune disease. 

Symptoms of Hypothyroidism in Newborns and Children

Congenital hypothyroidism symptoms in newborns may include the following:

  • Large tongue that appears swollen
  • Yellowish eyes and skin (Jaundice)
  • Constipation
  • Floppy and weak muscle tone
  • Sleeping more often and for longer than usual
  • The baby has a large fontanel (soft spot) on their head
  • The area around the eyes is swelled up
  • Slow and poor growth
  • The baby may have a large belly with a navel that sticks out
  • The skin of the infant is pale and feels cool

Congenital Hypothyroidism symptoms may also include breathing issues and lack of appetite. Hypothyroidism in newborn babies, if not treated in time, may contribute to the development of permanent mental disabilities. 

The Causes of Congenital Hypothyroidism

Most instances of congenital hypothyroidism are the result of aberrations in the prenatal development of the thyroid gland within the fetus. Upon birth, affected infants may exhibit either a complete absence of the thyroid gland or the presence of a diminutive, incompletely developed gland. The etiology of these developmental anomalies often remains elusive, though genetic factors are implicated in some instances.

Less frequently, congenital hypothyroidism ensues from the full maturation of the thyroid gland but its subsequent inability to synthesize normal quantities of thyroid hormone. This occurrence is primarily attributed to genetic aberrations. Notably, offspring born to the same parents harboring such genetic anomalies face a 25% likelihood of inheriting the same thyroid disorder.

Diagnosing Congenital Hypothyroidism in Newborns 

Establishing a timely diagnosis is crucial in every case. As such, all infants should undergo thyroid testing after birth as a part of standard, routine newborn screening.

Experts will typically draw a heel prick blood sample and test it for: 

  • High concentrations of TSH or thyroid stimulating hormone, which is produced by the pituitary gland. These hormones stimulate the thyroid gland, which, as a result, would increase its own production of hormones. 
  • Low levels of thyroxine or T4, which is a hormone produced by the thyroid, help control infant development and metabolism. 


In cases when the newborn screen test brings back abnormal results, experts will take an additional blood sample to verify their findings. In other instances, doctors may order imaging tests like thyroid scans and ultrasounds to gather even more information. 

Is Hypothyroidism Genetic?

In some cases, congenital hypothyroidism may have a genetic basis. While the exact cause of this congenital condition can vary, genetic factors can play a role. In certain instances, it may result from genetic mutations or abnormalities that affect the development or function of the thyroid gland or the production of thyroid hormones.

It is important to note that not all cases of congenital hypothyroidism are genetic, and the condition can also occur due to non-genetic factors, such as problems with thyroid gland development during fetal development. Additionally, some cases may be attributed to a combination of genetic and environmental factors.

Genetic testing and evaluation by a healthcare provider can help determine the underlying cause of congenital hypothyroidism in individual cases and whether it has a genetic component.

Treating Congenital Hypothyroidism

A child diagnosed with hypothyroidism typically undergoes thyroid hormone replacement therapy to compensate for the deficient production by the thyroid gland. In most cases, the administration of this medication is a lifelong necessity.

It is important to note that certain neonates may manifest transient hypothyroidism, a condition potentially induced by factors including premature birth, maternal thyroid dysfunction, or maternal medication usage during pregnancy. Notably, this variant of hypothyroidism often spontaneously resolves during the initial weeks or months of the infant’s life.

How Can Parents Help Their Children?

Little Girl Visiting Endocrinologist in Clinic

Administering thyroid hormone precisely as prescribed by the healthcare provider is of utmost importance when managing hypothyroidism in children.

For infants or very young children who are unable to ingest solid pills, the thyroid hormone medication can be crushed and mixed with a small quantity of water, non-soy baby formula, or breast milk. Optimal results are achieved by administering the medication at the commencement of feeding to ensure complete consumption. Notably, the dissolution characteristics of thyroid hormone pills in liquids can vary, necessitating consultation with a healthcare professional if difficulties arise.

Furthermore, caregivers should be aware that certain substances, including specific infant formulas (particularly soy-based formulations), medications, and mineral supplements like calcium and iron, may impede the absorption of thyroid medicine. Consequently, it is imperative to consult with a healthcare provider regarding the timing and administration of other medications or supplements when the child is concurrently taking thyroid hormones. This ensures that the child receives the full and intended dose of the medication, promoting effective treatment of hypothyroidism.

Routine medical assessments with your healthcare provider are essential to monitor the efficacy of the prescribed medication and to adjust the dosage in accordance with your child’s growth and development. It is imperative to diligently attend all scheduled follow-up appointments with your healthcare provider to facilitate optimal management of the condition.

It is noteworthy that children afflicted with Congenital Hypothyroidism may cause auditory impairments. If any concerns or questions arise regarding your child’s auditory or speech development, it is recommended to meet with your healthcare provider to address these matters comprehensively and ensure appropriate interventions, if necessary.

Expert Assistance a Call Away

If you would like to learn more about the condition and treatment, feel free to reach out to our experts. We are here to answer all your questions and concerns.