a disorder in which the
body is unable to use the
amino acids isoleucine,
leucine, and valine in a
normal way.
Excessive amounts of the branched-chain amino acids (valine,
leucine, and isoleucine) and their metabolites will build up in the
blood and spill into the urine and perspiration, giving them the
odour of maple syrup (which is how this disorder got its name).
caused by a deficiency of the
branched-chain ketoacid
decarboxylase enzyme
Clinical
presentation,
Newborn infants
present in the first
week of life with:
vomiting
difficult breathing
sleepiness
irregular muscle movement
seizures
coma
leading to death in
few weeks if
untreated
Diagnosis
Demonstration of the three
essential branched chain amino
acids in the blood
treatment
Basic treatment involves restricting foods
and infant formula which contain very small
amounts of leucine, isoleucine, and valine,
are used to provide the intake of protein
and other nutrients necessary for growth
Homocystinuria
Autosomal recessive
disorder of inherited
sulfur amino-acid IEM
Autosomal recessive
disorder of inherited
sulfur amino-acid IEM
clinical features
Dislocation
of the lense
Long fingers
(arachnodactyly)
Pectus
excavatum
Scoliosis
Learning
disability
Seizures
Thrombophilia
Diagnosis
1-Positive
cyanide
nitroprusside
test (detect
increased
levels of
homocystine in
urine)
2-Raised plasma homocystine level
3-Molecular studies to
detect mutations in genes
leading to deficiencies of
enzymes involved in the
synthesis of cofactors for
cystathionin B-synthase.