Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Idiopathic juxtafoveal retinal telangiectasia ?
    ### Response:
    What causes idiopathic juxtafoveal retinal telangiectasia? The exact, underlying cause of idiopathic juxtafoveal retinal telangiectasia (IJT) is not known. IJT has been reported in some siblings (including twins) and other family members of affected people.
    