Short Answer 
Arlo Guthrie chose not to undergo genetic testing for Huntington’s disease, which leaves uncertainty about his genetic status and potential risks. As of now, there is no indication that he has developed symptoms of the disease.
Step 1: Understanding Huntington’s Disease
Huntington’s disease is a debilitating genetic disorder caused by a dominant mutation. This means that an individual with just one copy of the altered gene will eventually develop the disease. Patients typically do not show symptoms until they reach middle age, raising challenging questions about inheritance and family planning.
Step 2: Arlo Guthrie’s Decision
Arlo Guthrie, the son of the famous folk musician Woody Guthrie, faced the choice of undergoing genetic testing to determine if he inherited the gene for Huntington’s disease. Acknowledging the risks, he decided against the testing, which left ambiguity surrounding his genetic status. It was a deeply personal decision that reflected his thoughts on family and the implications of passing on the disease.
Step 3: Current Status and Conclusion
As of now, there is no public information indicating that Arlo Guthrie has developed symptoms of Huntington’s disease. Ultimately, his decision not to pursue genetic testing means we do not know if he carries the gene. Therefore, the conclusion stands: he chose not to have genetic testing and did not develop the disease.