The patient is a 12-year-old male born at term with the use of forceps for stationary dilatation. Apgar and other postpartum examinations were normal. Rest was indicated during the last trimester of pregnancy due to threatened labour. During the postnatal period she presented delayed psychomotor development. At 3 years of age, she presented with absence seizures without subsequent epileptic seizures or need for treatment. Currently, she presents moderate mental retardation, learning difficulties, severe behavioural alterations in the autism spectrum, sphincter control deficit and attention deficit hyperactivity disorder, treated first with methylphenidate without improvement and, subsequently and up to the present, with antioxidants and improvement of the disorder. He also has social anxiety and extreme phobias to noises and animals, hypersensitivity to sounds, textures and certain foods, as well as chewing difficulties and secondary vomiting, generalised hypotonia, lax joints, valgus feet that have required surgery, and a significant sleep disturbance treated with melatonin. He has no cardiological or dysautonomic alterations or characteristic facial features.
The patient has an older healthy brother, but has a second cousin on the maternal side, aged 33 years, diagnosed at the age of 13 years with FXS after genetic testing. At that time the entire maternal side of the family was genetically tested and it was reported orally, without a written report, that both the patient's mother and her sisters were healthy carriers. This condition was not sufficiently appreciated by the family in the face of successive healthy children of the case patient's sisters and healthy brother. The case patient's mother did not receive genetic counselling or prenatal diagnosis indications in either of her two pregnancies. Only at her request was genetic analysis performed in the postnatal period in both cases.