Inborn Errors of Metabolism Flashcards
What mode of inheritance does Alkaptonuria have?
β Autosomal recessive
What happens during alkaptonuria?
β urine turns black on standing and alkalinisation
β black ochronotic pigementation of cartilage and collagenous tissue
β arthritis
What is alkaptonuria caused by?
β homogentisic acid oxidase deficiency
What is the mode of inheritance of cystinuria and how common is it?
β autosomal recessive
β 1 : 7000
What is the cause of cystinuria?
β mutations of SLC3A1 amino acid transporter gene (on chromosome 2p) and SLCA9 (chromosome 19)
What happens during cystinuria?
β defective transport of cystine and dibasic amino acids through epithelial cells of the renal tubule and intestinal tract
Why does cystine form calculi in the renal tract?
β low solubility
Who came up with the one gene one enzyme concept?
β Beadle and tatum 1945
What is the principle of the βone gene, one enzymeβ concept?
β Each biochemical reaction is under the ultimate control of a different single gene
β mutation of a single gene results in an alteration in the ability of the cell to carry out a single primary chemical reaction
Who came up with the molecular disease concept?
β Pauling et al
What is the molecular disease concept?
β direct evidence that human gene mutations produce an alteration in the primary structure of proteins
β Inborn errors of metabolism are caused by mutations in genes which then produce abnormal proteins whose functional activities are altered
What is autosomal recessive?
β when both parents carry a mutation affecting the same gene
What is the risk of a child with a disorder if the inheritance is autosomal recessive?
β 1 in 4 risk
What increases the risk of an autosomal recessive disorder?
β consanguinity
What are two examples of autosomal recessive diseases?
β sickle cell
β cystic fibrosis
What are 3 examples of autosomal dominant disorders?
β Huntingtons
β Marfans
β familial hypercholesterolemia
How are X linked conditions passed?
β through the maternal line
Who has the condition in X linked inheritance?
β condition appears in males
How can female carriers manifest an X linked condition?
β Random inactivation of one X chromosome (Lyonization)
How are dominant X linked conditions passed on?
β from either parents
Who will an affected father of an X linked condition pass it on to?
β only to daughters
Who will an affected mother of an X linked condition pass it on to?
β sons and daughters
What are 2 examples of X linked dominant conditions?
β Fragile X
β Ornithine carbamoyltransferase deficiency
What are 3 examples of X linked recessive conditions?
β Haemophilia A
β Duchenne muscular dystrophy
β Fabryβs disease
