Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) isodicentric chromosome 15 syndrome ?
    ### Response:
    Isodicentric chromosome 15 syndrome is a developmental disorder with a broad spectrum of features. The signs and symptoms vary among affected individuals.  Poor muscle tone is commonly seen in individuals with isodicentric chromosome 15 syndrome and contributes to delayed development and impairment of motor skills, including sitting and walking.
    