Galactosemia

By

Farshid Mokhberi

Shahid Beheshti University of Medical Science

Galactosemia

Galactosemia :

is a rare genetic metabolic disorder that affects an

individual's ability to metabolize the sugar galactose

properly.

Galactosemia follows an autosomal recessive mode of

inheritance that confers a deficiency in an enzyme

responsible for adequate galactose degradation.

Galactosemia and organs:

TYPES:

Type OMIM Gene Locu

s

Enzyme Name

Type 1 230400 GALT 9P13 Galactose1-

phosphat uridyl

transferase

Classic

galactosemia

Type 2 230200 GALK1 17q24 galactokinase Galactokinase

deficiency

Type 3 230350 GALE 1p36-

p35

UDP galactose

epimerase

UDP-Galactose-

4-epimerase

deficiency

Galactose is converted into glucose by the action of three enzymes,

known as the Leloir pathway:

Gene location:GALE

GALT

GALK1

Normal metabolic pathway for galactose

in humans:

Sign and symptoms:

Intellectual disability

Hepatomegaly

Hepatic failure

Renal failure

Cataract

Premature ovarian failure

Dysmetria

Ataxia

Diagnosis:

Galactosemia is normally first detected through newborn screening, or NBS.

A galactosemia test is a blood test (from the heel of the infant) or urine test that checks for three enzymes that are needed to change galactose sugar that is found in milk and milk products-into glucose. A person with galactosemia doesn't have one of these enzymes. This causes high levels of galactose in the blood or urine.

Screening tests:

Beutle’s test:

Beutle's test: also known as the

fluorescent spot test, is a screening

test that used to identify enzyme

defects.

Treatment:

The only treatment for classic

galactosemia is eliminating lactose

and galactose from the diet.

Gene therapy

Galactosemia is sometimes

confused with lactose intolerance: Galactosemia is a more serious

condition. Lactose intolerant individuals have an acquired or inherited shortage of the enzyme lactase, and experience abdominal pains after ingesting dairy products, but no long-term effects. In contrast, a galactosemic individual who consumes galactose can cause permanent damage to their bodies.

Thanks for

your

attention

Refrenses:

http://ghr.nlm.nih.gov/gene/GALK1

http://ghr.nlm.nih.gov/gene/GALE

http://ghr.nlm.nih.gov/gene/GALT

www.ncbi.nlm.nih.gov/guide/genetics-

medicine

http://www.ncbi.nlm.nih.gov/gap