How will Phenylketonuria affect the inidividuals suffering from it?

Because Phenylalanine is an Essential amino acid that is inquired through our diet. When PAH (the enzyme to breakdown Phenylalanine) is deficient or is insufficient, phenylalanine will accumulate in blood and body tissues. Accumulation of phenylalanine in all bodies liquids and they are excreted in the urine of the transformation product phenylpyruvate (phenylketon). 

Chronically high levels of phenylalanine cause significant health problems.

Signs and symptoms of PKU vary from mild to severe. 
Mild case of disorder is known as variant PKU or non-PKU hyperphenylalaninemia whereas severe form of this condition is known as classic PKU.

·         Variant PKU
-Face lesser risk of brain damage and their treatment may not require low phenylalanine diet.

·         Classic PKU
--- Children with classic PKU tend to have blue eyes and lighter skin and hair than unaffected family members  (this is because our body process phenylalanine into tyrosine which produce melanine, Melanine cause darker skin and eyes)  and are also likely to have skin disorders such as eczema.

--Infants with classic PKU appear to be normal until they are a few months old.
-Some early symptoms are vomiting, irritability, having eczema-like rashes and a mousy odour to their urine.
-without treatment, these babies develop permanent intellectual disability and suffer from severe brain damages like seizure (Epilepsy), mental retardation and also cause behavioral problems. Other commonly noted features in untreated children include: Small head (microcephaly), prominent cheek and upper jaw bones with widely spaced teeth, poor development of tooth enamel, and decreased body growth.

Babies born to mothers with PKU and uncontrolled phenylalanine levels (women who no longer follow a low-phenylalanine diet) have a significant risk of intellectual disability because they are exposed to very high levels of phenylalanine before birth. These infants may also have a low birth weight and grow more slowly than other children. Other characteristic medical problems include heart defects or other heart problems, an abnormally small head size (microcephaly), and behavioral problems. Women with PKU and uncontrolled phenylalanine levels also have an increased risk of pregnancy loss.  

Newborn screening, early identification, and management are part of the treatment for PKU and these can lessen the babies’ suffering like vomiting and eczema skin problems. By recognizing phenylketonuria right away can help prevent serious health problems.

References:
(2012). Phenylketonuria. Retrieved June 21, 2012, from Genetics Home Reference, your guide to understand genetic conditions: http://ghr.nlm.nih.gov/condition/phenylketonuria

(1985) Phenylketonuria (PKU). Retrieved June 21, 2012, from MedHelp: http://www.medhelp.org/lib/pku.htm

(2011) Phenylketonuria – MayoClinic.com. Retrieved June 21, 2012, from Mayo Clinic: http://www.mayoclinic.com/health/phenylketonuria/DS00514

[Phenylketonuria Symptoms] Retrieved June 21, 2012, from http://img1.ranker.com/list_img/1/335486/full/phenylketonuria-symptoms.jpg?version=1319277657000 
(2012).  Amino acid metabolism. Retrieved June 21, 2012, from A blockade in the degradation of phenylalanine can lead to mental retardation: http://www.natuurlijkerwijs.com/english/Aminozuurstofwisseling.htm

Phenylketonuria....?

Why is it called Phenylketonuria?

The name of this disease actually come from Phenylalanine & one of the dominant metabolites which contains a ketone group (phenylpyruvate, an alpha-keto acid) circled in red in the pic above.

Introduction to Phenylketonuria. Retrived July 1, 2012, from http://www.uic.edu/classes/phar/phar332/Clinical_Cases/aa%20metab%20cases/PKU%20Cases/PKU%20biochem%20intro.htm

What causes Phenylketonuria?

Phenylketonuria (PKU) is an inherited disorder from autosomal recessive gene for metabolism.
 There is mutation in the gene that produces phenylalanine hydroxylase (PAH). PAH is used to break down phenylalanine. Phenylalanine is an amino acid that can be found in many food with protein. The mutation can cause reduction in the enzyme activity or not functioning at all, depending on the severity. When PAH is not working properly, phenylalanine cannot be processed efficiently and will begin to accumulate to toxic level in the human blood and tissue.

Reference:
(2012). Phenylketonuria. Retrieved June 21, 2012, from Wikipedia, the free encyclopedia Web site: http://en.wikipedia.org/wiki/Phenylketonuria#Metabolic_pathways.

(2012). Phenylketonuria. Retrieved June 21, 2012, from Genetics Home Reference, your guide to understand genetic conditions: http://ghr.nlm.nih.gov/condition/phenylketonuria.