You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Which is not true about Fragile X syndrome and explain in detail?
Fragile X syndrome is associated with the loci Xq27.3 on the distal long arm of the X chromosome. In affected males, it is mainly characterized by mental retardation, macroorchidism, autistic behaviour, facial features like long face, large ears, prominent square jaw Pigmented naevi are not seen associated with fragile X syndrome. Reference : Nelson paediatrics 19th edition pg 411