Health Professionals Guide to Newborn Screening

Homocystinuria & Hypermethioninemia

Autosomal recessive amino acid disorder caused primarily by a deficiency in cystathionine beta synthase enzyme activity causing the build up of the amino acid methionine in the blood. Early detection and treatment can prevent associated mental retardation, seizures, motor development delays, weakening of bones, and venous and arterial blood clots.

Prevalence (WI):	1:119,000 (general population)
Analyte Measured:	Methionine
Abnormal Levels:	³ 100 µmol/L
Feeding Effect:	None
Timing Effect:	< 24 hours of age: Repeat at two weeks ³ 24 hours of age: Results are valid
Confirmation:	Immediate consult with a metabolic specialist at a metabolic treatment center.
Treatment:	The treatment for homocystinuria is the dietary restriction of methionine as well as large doses of vitamin B6 and betaine.

Information on treatment centers is also available on this site.

For information about other screened disorders, click on the next page button, or follow one of these links:

• Argininosuccinic Acidemia (ASA)	• Hemoglobin Variants
• Biotinidase Deficiency	• Homocystinuria
• Congenital Adrenal Hyperplasia	• Hypermethioninemia
• Congenital Hypothyroidism	• Hyperphenyalaninemia
• Citrullinemia (Types I & II)	• Maple Syrup Urine Disease
• Cystic Fibrosis	• Organic Acidemias (14)
• Fatty Acid Oxidation Disorders (12)	• Phenylketonuria (Includes Biopterin Cofactor defects of regeneration and biosynthesis)
• Galactosemia	• Severe Combined Immune Deficiency (SCID)
• Hemoglobin S-Beta Thallassemia	• Sickle Cell Disease
• Hemoglobin S/C Disease	• Tyrosinemia (Types I,II, & III)

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