[Perinatal asphyxia as incorrect explanation for mental retardation].

Three women, aged 21, 34 and 32 and with a family history of mental retardation said to be caused by perinatal asphyxia, each gave birth to a child with mental retardation. A chromosomal translocation, fragile X syndrome, and myotonic dystrophy could be diagnosed, respectively. In retrospect, the diagnosis of perinatal asphyxia in the family history had been too readily accepted. In reality the mental retardation was caused by a genetic disorder. Physicians are used to making a diagnosis, and when a diagnosis is not (yet) possible, they try to establish a working diagnosis or differential diagnosis. Too often such a working diagnosis becomes, through time, a definite diagnosis.