Learning disabilities tend to run in families. Very often one parent has a history of specific learning problems (like dyslexia) or problems in certain areas of academic functioning. They can have specific problems with auditive information, written information or arithemics. But it is rather unlikely that specific learning disorders are directly inherited. Biologists think that a couple of different genes may influence the later development of learning disabilities. More genes with symptomatic changes might cause more severe disabilities. Possibly, what is inherited is a subtle brain dysfunction that can in turn lead to a learning disability.
New research tries to identify biological causes of learning disabilities like dyslexia. New methods of functional neuroantomomy with PET or SPECT-Scans show differences in structure and functioning of the brain.
For example, new research indicates that there may be variations in the brain structure called the planum temporale, a language-related area found in both sides of the brain. In people with dyslexia, the two structures were found to be equal in size. In people who are not dyslexic, however, the left planum temporale was noticeably larger. Some scientists believe reading problems may be related to such differences.
More research is going on in this area of psychiatry. The future results may help to understand the function of these brain areas and help to optimize treatment approaches for these children.