The document discusses three types of inborn errors of metabolism: phenylketonuria, which is caused by a recessive gene preventing the conversion of phenylalanine to tyrosine, leading to accumulation of phenylalanine derivatives; alkaptonuria, caused by a recessive gene preventing the conversion of homogentistic acid, turning the urine black; and albinism, a recessive condition preventing the production of the enzyme tyrosinase needed to produce melanin pigment.

1. INBORN ERRORS OF
METABOLISM
DR.V.JEYANTHI KUMARI,
ASSISTANT PROFESSOR OF ZOOLOGY,
A.P.C.MAHALAXMI COLLEGE FOR WOMEN,
THOOTHUKUDI-2
TAMIL NADU.

2. Metabolic disease due to the presence of recessive
genes from birth is called inborn error metabolism
Coined-Grand-1909
3 types
1.Phenylketonuria
2.Alkaptonuria
3.Albinism

3. • PHENYLKETONURIA
• Hereditary disease
• Recessive gene pp
• No production-phenylalanine hydroxylase
• Phenylalanine hydroxylase
• Phenylalanine Tyrosine
• P.alanine derivatives like phenyl pyruvic acid. Phenyl
acetic acid accu in blood, csf
• Excess in urine
• Child called phenyl pyruvic idiots.
• Mental defeat, feeble mindedness, etc.

4. • ALKAPTPNURIA
• hh
• The accumulation of alcapton (homogentistic
acid)
• No-homogentistic acid oxidase
• No conversion of alcapton to acetoacidic acid
• Accumu in blood
• Urine turn black
• homogentistic acid
oxidase
• P.alanine……>Tyrosine…>Alcapton….>Aceto
acetic acid

5. ALBINISM
• aa
• tyrosinase
• Ph.alanine…>tyrosine……….. Melanin….>normal