Phenylketonuria (PKU) Facts
Phenylketonuria (PKU) is a genetic disorder that causes the amino acid phenylalanine to build up in the blood. This results in severe and irreversible mental retardation, especially in infants, if not treated early.
There is little information available on the incidence of PKU. In the United States, research reports:
Cause and Incidence
In PKU, the child lacks or has very low levels of the enzyme phenylalanine hydroxylase (PAH). PAH is necessary to convert phenylalanine into another amino acid, tyrosine. If phenylalanine is not converted, it builds up in the bloodstream and disturbs the metabolism, resulting in mental retardation. Phenylalanine is a component of protein, so when protein is consumed, phenylalanine builds up in those people with PKU.
At birth, babies with PKU have no signs or symptoms of the disorder because the mother's body filters out phenylalanine for her unborn baby before birth. Symptoms appear after the baby starts consuming protein (from either breast milk or formula), and the resulting phenylalanine builds up in his or her system, usually by a few months of age. If PKU is not treated, it usually causes progressively severe mental retardation and other problems affecting the nervous system. The baby will not be able to regain the lost mental ability.
PKU is an autosomal recessive disease. This means that to have the disease, a person must inherit a gene from both parents. If a person inherits the gene from only one parent, he or she is a carrier. This means that the person carries the gene for PKU, but does not have the disease.
In the United States, babies are routinely tested for PKU shortly after birth so that early diagnosis and treatment are possible and so that injury to the baby's brain is usually prevented. Treatment for PKU consists of a special diet containing reduced amounts of protein (which contains phenylalanine). Phenylalanine is essential for normal growth and development and cannot be eliminated from the diet.
If PKU is treated by 3 weeks of age, the baby may not have any permanent brain damage. Rarely, children may have learning or behavior problems (such as slower language development, hyperactivity, anxiety, and poor concentration) despite early treatment.
Women of childbearing age who have PKU must be very careful. High blood levels of phenylalanine during pregnancy can result in babies with mental retardation, small heads (microcephaly), retarded physical growth, and heart-related risks such as congenital heart disease
If you have a family history of phenylketonuria, talk with your health professional about genetic testing. If you have a child with PKU, seek genetic counseling before attempting another pregnancy.Symptoms
Signs and symptoms of phenylketonuria (PKU) include:
If phenylalanine rises above an acceptable level, the child almost always:
Children with PKU tend to be blond with fair skin and blue eyes. This is because PKU affects the synthesis of melanin, which provides pigment (color) to the skin, eyes, and hair.
Some people with PKU have more severe symptoms than others because of variations in the disease.
If you think your new baby has symptoms of phenylketonuria, talk with your health professional about whether the baby was tested adequately. Early diagnosis and treatment for PKU can prevent mental retardation. See the Exams and Tests section of this topic for more information on testing.Source: Healthwise, Inc.
AIHC || AIHC Home || Health Section || Cultural Section || AIHC's Links || Outreach || Webrings || Useful Hotlines || Win Our Awards! || Awards We've Won || Health Section || Acanthosis Nigricans || Ankylosing Spondylitis || Asthma Facts || Bi-polar Disorder Facts || Breast Cancer Facts || Cataracts || Cervical Cancer Facts || Chlamydia Facts || Colon Cancer Facts || Cystic Fibrosis || Chronic Fatigue Syndrome || Depression Facts || Diabetes Facts || Diabetes, Type 2 || Diabetic Retinopathy || Diptheria Facts || Domestic Violence || Eating Disorders || Elder Women's Health Facts || Elder Abuse Facts || FAS/FAE Facts || Gallbladder Disease Facts || Gestational Diabetes || Gonorrhea Facts> || Heart Disease Facts || Hepatitis Facts || HIV/AIDS Facts || Hypertension Facts || Hypothyroidism Facts || Insulin Resistance Syndrome || Kidney Disease || Lactose Intolerance || Lung Cancer || Lupus Facts || Menopause Facts || Multiple Sclerosis || Obesity Facts || Oral Clefting || Osteoporosis Facts || Parkinson's Disease || Personality Disorders || Phenylketonuria (PKU) Facts || Polycystic Ovary Syndrome (PCOS) || Pneumonia Facts || Pre-Diabetes || Proteinuria Facts || Rheumatoid Arthritis || Reye's Syndrome || Schizophrenia Facts || Scleroderma Facts || Seizure Disorders || Stroke Information || SIDS || Substance Abuse Facts || Suicide Prevention || Testicular Cancer || Tobacco Abuse || Traditional Herbal Medicine || Tuberculosis Facts ||