text: how do docters diagnose jacob's syndrome?   since there are no real characteristics to this syndrome, the doctor will not know that a male has this unless the patient is in need of genetic testing for another reason such as testing the paternaty of a child.  this syndrome is only characterized by physical symptoms all of which can be related to other health problems.  so the long and short of it is a dna test can determine if you have jacob's syndrome.  hope this answers your question right along with my resource.