<prompt> Mild MR features area Present in 510 populationb Incidence in low socioeconomic groupc Presents in 2 yearsd Genetic background Presentcdbdac  <response>: Mental retardationMental retardation MR refers to a group of disorders that have in common deficits of adaptive intellectual function an age of onset before maturity is reached.According to statistics, 2.5 of the population should have MR, 85 of these individuals should fall into the range of mild MR.PresentationMR presents by the age of the patient, i.e.Newborn : Dysmorphism, major organ system dysfunction.Early infancy 2-4 months : Failure to interact with the environment, vision hearing impairment.Late infancy : Gross motor delayToddlers 2-3 yrs : Language delays difficulties.School age over 5 yrs : Academic underachievement behaviour difficulties.Predisposing factors for mental retardationi Low socio - economic strata iii Advanced maternal age v Genetically transmittedLow birth weight iv Consanguinity 