文档介绍：11 单基因遗传病(B) Single Gene Disorder (B)
2. Inborn Errors of Metabolism
Inborn errors of metabolism are rare ic disorders in which the body cannot turn food into energy (metabolize food) normally. The disorders are usually caused by defects in the enzymes involved in the biochemical pathways that break down ponents.
In 1904 the doctor Archibald E. Garrod
described alkaptonuria, a disease he classified as a
lifelong congenital chemical
alteration. Later on, in 1909,
he described other diseases:
albinism, cystinuria,
porphyria and pentosuria,
which he named "Inborn
Errors of Metabolism". Garrod's
conclusions pletely
correct in relation to the ic
basis of metabolic disorders and
the gene-enzyme concept.
The gene defect can cause a particular enzyme to be defective or missing. And because the enzyme isn't doing what it is supposed to do for the body, poor health may result.
Simply put, enzymes help the body by stimulating biological reactions inside cells. Enzymes are proteins that help the body use food, produce energy, and do work. When a particular enzyme is defective or missing, then the body isn't able to do something that it should do to maintain health. The enzyme involved determines what the body can't do and what the resulting physical features are.
Inborn errors of metabolism affect about 1 in every 5,000 babies born. Some of the more familiar inborn errors of metabolism are cystic fibrosis, hypothyroidism,, phenylketonuria (PKU) and Tay-Sachs disease.
The symptoms of inborn errors of metabolism vary greatly. Each one must be reviewed separately to know what the physical features are. Often, an infant will show signs of failure to thrive by failing to gain weight, not eating well, and generally showing developmental delay. Vomiting and diarrhea are among other symptoms that may signal the healthcare provider to test for an inborn error of metabolism.
Metabolic defect
Results in
Onset
Example
Energy generation
Energy deficit
Hypoglycemia