Down-en sindromea (DS) penetrantzia osoa duen genetikoki zehaztutako Alzheimer-en gaixotasunaren (AG) sortzaile da. Memoria ardatz nagusi duen narriadura kognitiboa da abiapuntu ohikoena. Bizi-itxaropenak 60 urte gainditzearen ondorioz, AGaren garrantzia nabarmen handitu da DSarenbarnean. Diagnostiko goiztiarra egitea posible da gainerako AG kasuetan bezalaxe, nahiz eta horretarako ezinbestekoa den azterketa neurologiko eta neuropsikologiko espezializatu bat egin ahal izatea. Narriadura kognitiboa dagoela zehaztu ostean, biomarkatzaileek diagnostikoa bermatzen laguntzen dute gainerako AG kasuetan bezalaxe. Horrek AGaren sintomak tratatzea ahalbidetzen digu eta baita AGari loturik sarritasun handiagoarekin ageri diren beste osasun-arazoenak ere (epilepsia eta lo-arazoak, esaterako). Diagnostiko eta tratamendu goiztiar eta egokiek DSa duten pertsona eta haienzaintzaileen bizi-kalitatea hobetu dezakete. Gako-hitzak: Alzheimer-en gaixotasuna, Down-en sindromea, narriadura kognitiboa, diagnostiko goiztiarra, biomarkatzaileak. Alzheimer's disease in Down syndrome Down syndrome (DS) is the cause of fully penetrant genetically determined Alzheimer’s disease (AD). Memory-focused cognitive impairment is the most common initial symptom. As life expectancy has risen above the age of 60, the number of cases of AD among the DS population has increased. As in other cases of AD, early diagnosis is possible, although it is necessary to be able to carry out a specialist neurological and neuropsychological examination. Once the existence of cognitive impairment has been detected, as in other cases of AD, biomarkers help confirm the diagnosis. This enables the symptoms of AD to be treated, along with other health issues that most frequently accompany this disease (epilepsy and sleep disruption, for example). Early diagnosis and proper treatment of AD can improve the quality of life of people with DS and their caregivers. Keywords: Alzheimer’s disease, Down syndrome, cognitive impairment, early diagnosis, biomarkers