Congenital Hypothyroidism

Other Names

Cretinism

Congenital myxedema

Diagnosis Coding

E03.0, congenital hypothyroidism with diffuse goiter

Disorder Category

An endocrine disorder

Screening

Finding

Elevated TSH

Tested By

Thyroid stimulating hormone (TSH), and thyroxine (T4)

Overview

Of the causes of congenital hypothyroidism, thyroid agenesis and ectopic thyroid comprise about 75-80% and inborn errors in thyroid hormone synthesis, dysfunction of the hypothalamic-pituitary axis, and thyroid hormone receptor defects comprise the rest. The inborn errors include: thyroid stimulating hormone (TSH) receptor defects, abnormalities of iodide uptake, abnormality in iodide to iodine conversion (peroxidase defect, Pendred syndrome), thyroglobulin defect, and deiodinase defect. Iodine deficiency during pregnancy contributes to congenital hypothyroidism still in many countries. About 10% of those identified by newborn screening will have transient hypothyroidism, often secondary to maternal factors. Though physical findings and symptoms may not be apparent until a few months of life, central nervous system injury may occur during that time.

Prevalence

Congenital hypothyroidism occurs in about 1:3,700 live births. The incidence is increased in Hispanic infants, in girls, and in twins, and decreased in boys and in African-Americans. Infants with Down syndrome have a 35-fold increased risk.

Inheritance

Most cases are sporadic, but about 15% are inherited as autosomal recessive. Several gene mutations are known to cause congenital hypothyroidism.

Other Testing

Newborn screening results may be normal in infants with clinical symptoms. Additional testing is recommended when clinical symptoms are present. False-positive testing may result from samples taken within the first 48 hours of life. Retesting is suggested.

Clinical Characteristics

With early treatment, normal growth, development, and IQ can be expected. Without treatment, affected individuals will increasingly develop symptoms as described below, along with growth retardation and irreversible neurodevelopmental impairment.

Only about 5% of infants have detectable physical findings or symptoms at birth. Inital signs and symptoms may include:
  • Hypotonia
  • Umbilical hernia
  • Puffy face
  • Large tongue
  • Large fontanelle
  • Short fingers and broad hands
  • Short legs and arms
  • Hyperreflexive jerk with marked slowing of return phase
  • Hoarse-sounding voice or cry
  • Mottled, cool, dry skin
  • Goiter
If untreated, signs and symptoms that may develop over the subsequent weeks include:
  • Prolonged jaundice
  • Constipation
  • Feeding problems
  • Distended abdomen
  • Lethargy

Follow-up Testing after Positive Screen

Serum free T4 and TSH.

Primary Care Management

Upon Notification of the + Screen

If the Diagnosis is Confirmed

  • Educate the family regarding signs and symptoms.
  • Levothyroxine is indicated for affected children and should be monitored and adjusted in collaboration with a pediatric endocrinologist.
  • For those identified after irreversible consequences, assist in management, particularly with developmental and educational interventions.

Specialty Care Collaboration

Initial consultation and ongoing collaboration, particularly for medication management. Genetic counseling for the family may be indicated.

Resources

Information & Support

For Professionals

ACT Sheet for Elevated TSH (ACMG) (PDF Document 349 KB)
Contains short-term recommendations for clinical follow-up of the newborn who has screened positive; American College of Medical Genetics.

ACT Sheet for Low T4 and/or Elevated TSH (ACMG) (PDF Document 348 KB)
Contains short-term recommendations for clinical follow-up of the newborn who has screened positive; American College of Medical Genetics.

Newborn Screening ACT Sheets & Confirmatory Algorithms (ACMG)
ACTion (ACT) Sheets and algorithms for responding to positive newborn screening test results, membership required; American College of Medical Genetics.

Resource for Congenital Hypothyroidism (NLM)
Comprehensive compilation of links to information, articles, research, case studies, genetics, and more; from the National Library of Medicine and the Genetic Alliance.

Utah Newborn Screening Program (UDOH)
Provides information about the program, related legislation, training for practices, and newborn conditions; Utah Department of Health.

Genetics in Primary Care Institute (AAP)
The goal of this site is to increase collaboration in the care of children with known or suspected genetic disorders. Includes health supervision guidelines and other useful resources; a collaboration among the Health Resources & Services Administration, the Maternal and Child Health Bureau, and the American Academy of Pediatrics.

Congenital Hypothyroidism: Provider Fact Sheet (UDOH) (PDF Document 94 KB)
Information about screening updates, signs and symptoms, and essential steps for diagnosis and treatment; Utah Department of Health/Newborn Screening Program.

For Parents and Patients

Congenital Hypothyroidism (Genetics Home Reference)
Excellent, detailed review of condition for patients and families; U.S. National Library of Medicine.

Congenital Hypothyroidism: Parent Fact Sheet (UDOH)
Information for families immediately after receiving a diagnosis; Utah Department of Health Newborn Screening Program.

The Magic Foundation
A non-profit organization, providing support services for families of children with a wide variety of chronic and/or critical disorders, syndromes, and diseases that affect growth. Offers some prescription and appeals financial assistance.

Services

Genetics-related clinical services throughout the world can be found through Genetics Clinic Directory (GeneTests).

Newborn Screening Programs

See all Newborn Screening Programs services providers (3) in our database.

Pediatric Endocrinology

See all Pediatric Endocrinology services providers (2) in our database.

For other services related to this condition, browse our Services categories or search our database.

Authors

Reviewing Author: Nicola Longo, MD, PhD - 3/2007
Content Last Updated: 3/2008