Congenital hypothyroidism

Alternative name	Primary congenital hypothyroidism
About the condition	Congenital hypothyroidism is an endocrine disorder. It is a condition that is caused by under-activity of the thyroid gland, which results in low levels of thyroid hormones. These hormones play an important role in body metabolism and their deficiency can cause intellectual and physical disability.
Inheritance	Most cases are sporadic. However, about 10% of cases result from inherited enzyme defects within the thyroid gland.
Year screening occurred in WA	1981
Incidence in WA	1 in 3,000 births
Defect	No thyroid gland (athyrosis) Small maldescended gland Iodination defect
Symptoms if untreated	Signs of hypothyroidism often do not appear until the infant is 3–4 months of age. Affected infants are likely to have already suffered irreversible brain damage before signs of the condition begin to appear. Many times the early diagnosis relies almost solely on the results of newborn screening. Other symptoms of the condition include: Prolonged neonatal jaundice Feeding problems, FTT, constipation Lethargy, hypotonia Coarse facial features, thick tongue Hoarse cry Distended abdomen, umbilical hernia Intellectual disability Physical disability If detected early and treated, the child will develop normally.
Metabolites on bloodspot screening	Increased thyroid stimulating hormone (TSH).
Diagnostic tests	Plasma TSH and free T4 A scan of the thyroid gland is also sometimes performed
Treatment	Daily treatment with thyroid hormone tablets results in normal growth and development.
Screening issues	The screening results may be affected by maternal thyroid disease and medication, as well as iodine excess or deficiency.