[Diagnosis and genetic counseling in mental retardation]. / Acercamiento diagnóstico y asesoramiento genético en el retraso mental.

An accurate diagnosis of a mentally retarded patient is a crucial step to design a successful treatment. The effects of genetic and environmental influences have to be clarified in the etiological approach. For that reason, we have to record a more appropriate family information, detailed prenatal, birth and postnatal patient history, and perform a thorough clinical examination to check for associated major and minor malformations. One of the major question to be resolved when faced with a mentally retarded patient is whether the disease is genetically or environmentally determined. The main purpose of this paper is to describe a general methodology we apply in genetic counselling of mental retardation including diagnosis, risks evaluation and psychological steps that we have to consider when we inform family members at risk.