HPA is a recessive hereditary disease, also known as hyperphenylalaninemia, and babies born with the disease will have an impact on their mental development as they get older, and will have a peculiar odor in their urine. Infants with hyperphenylalaninemia need to be screened for the hereditary disease with a plantar blood test three days after birth, and early intervention with a low-phenylalanine formula will provide some relief. Infants with this genetic disorder are caused by a lack of the enzyme phenylalanine-enhancing enzymes in the body, which prevents phenylalanine from being metabolized. Women who have given birth to such babies should have chromosomal screening before the next pregnancy to try to detect and avoid the birth of such hereditary diseases.