The essay concentrates on the single gene defects, looking initially at the types of mutations which effect genes and then moving on to the three major groups of these disorders; autosomal recessive, autosomal dominant and sex-linked. Each of these groups accompanied by at least one example and within the autosomal recessive disorders, haemoglobinopathies are discussed. There is then a brief discussion about the molecular basis of some cancers and the other groups of human molecular diseases.
Human molecular diseases cover a vast range of disorders that are caused by genetic mutations. There are many different types of mutations yet they cause disease in two main ways; affecting the quantity or the function of the gene product. Much about molecular diseases is still unknown due to the complexity of such diseases and the effects of other factors such as environmental factors. The field is however developing quickly with ever growing knowledge of gene structure and functions, from projects such as the Human Genome project.
A large proportion of human molecular diseases are caused by ¡®single gene defec
¡®Molecular Medicine¡¯ by John Bradley, David Rubenstein and David Johnson.
Transcription Mutations Mutations in a promoter region of the ¦Â-globin gene. Decrease in transcription of ¦Â-globin mRNA.
(This diagram shows the X-linked inheritance of Duchenne muscular dystrophy when the mother carriers the gene. It can be seen how a son has 50% probability of being affected by the disorder.)
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