inherited metabolic diseases Flashcards
what is a guthrie card used for ?
blood spot screening in egypt is used to test and screen for PKU and hypothyroidism in the UK : MCADD CF SCD PKU congenital hypothyroidism
what is the genetic inheritance associated with PKU ?
autosomal recessive
what is the cause of PKU ?
deficiency of phenylalanine hydroxylase enzyme
what are the effects of untreated PKU ?
severe intellectual disability behavioural difficulties seizures lack of pigmentation eczema and atopic dermatitis musty or mousy odor
what would a brain MRI associated with PKU show ?
demyelination areas of demyelination
how is a diagnosis of PKU made ?
elevated phenylalanine and a deficiency of tyrosine
guthrie test
what are the general treatment methods or approaches associated with PKU ?
substrate reduction therapy
enzyme enhancement therapy
enzyme replacement therapy
large neutral amino acids
what are the associated results of early intervention in PKU with substrate reduction ?
if the PHE level is kept below 400 in early childhood IQ remains near normal
what is the correlation between an increase in PHE and IQ levels in children
each increase by 300 mcmol in PHE
IQ decreases by 0.5 SD
After the age of 10 IQ remains stable
what are the indications associated with a PKU diet ?
low protein diet
protein exchanges
what are protein exchange foods ?
equivalent to 1 g of protein or 50 mg of PHE
how is enzyme supplementation therpay achieved in PKU ?
- Sapropterin supplementation , which is a cofactor for PAH
Used in conjunction with low PHE diet
how is an nalternative route of metabolism achieved in the treatment of PKU ?
palynziq is used in the form of SC injections
how are large neutral amino acids used in the treatment of PKU ?
competitive inhibition of the uptake of PHE through the BBB , so the negative effects imposed on the brainn are reduced
what are the different examples of lysosomal storage diseases ?
Gaucher disease
MPS I - Hurler
MPS IV - Morique
what is the method of inheritance associated with lysosomal storage diseases ?
autosomal recessive
what is the course of lysosomal storage diseases ?
progressive course
what is the presentation of gaucher disease ?
painless splenomegaly, anemia, or thrombocytopenia
what is the presentation of MPS I ?
hurler
coarse face
corneal clouding
what is the presentation in MPS IV ?
anterior beaking of vertebrae
scoliosis
kyphosis
what is Pompe disease ?
a type of glycogen storage disease ( GSD type 1)
which enzyme is deficient in Pompe disease ?
alpha glucosidase deficiency also named AMD
how is pompe disease treated ?
using enzyme replacement therapy ( replacement through GAA)
what is the presentation of Pompe disease ?
pelvis muscle weakness
scapular winging
FTT
weak muscles
what is the enzyme replacement therapy for each of these diseases : Gaucher Fabry MPS I MPS VI GSD II
gaucher - cerezyme Fabry - fabrazyme MPS I - aldurazyme MPS VI - Naglazyme GSD II - Myozyme
