Genetic Testing In Newborns: Common Tests
Newborns are commonly screened for a variety of conditions at birth using genetic testing. Among the disorders for which genetic testing in newborns is carried out, the following are most commonly available today:
Biotinidase Deficiency (BIO) an enzyme deficiency that causes seizures, hearing loss and death in severe cases. Early detection helps since the treatment is simple and requires daily doses of biotin.
Congenital Adrenal Hyperplasia (CAH) is due to lack of production of certain adrenal hormones. Early detection can prevent mortality in both boys and girls and sex misassignment in girls.
Congenital Hypothyroidism (CH) is caused by insufficient or total lack of production of thyroid hormone. Thyroid hormone replacement therapy can be started as early as 1 month of age and prevents mental as well as growth retardation.
Congenital Toxoplasmosis (TOXO) refers to infection of the fetus with a parasite ingested by the mother during pregnancy resulting in TOXO in the newborn. Early diagnosis and resultant therapy decreases the incidence of blindness, mental retardation and other serious complications.
Galactosemia (GAL) is a disorder in which the newborn shows failure to metabolize the milk sugar galactose. The classical form detected by newborn genetic testing causes cataracts, liver cirrhosis, mental retardation and/or death.
Homocystinuria (HCY) is due to an enzyme deficiency which blocks the metabolism of an amino acid leading to mental retardation, osteoporosis and other problems if not detected.
Medium Chain Acyl-CoA Dehydrogenase (MCAD) Deficiency is a common disorder which can cause sudden death when left undetected. The incidence from newborn screening is not yet known since this is a relatively recent introduction in genetic testing in newborns.