Two proteins particularly relevant in the context of T21 were emphasized, namely apolipoprotein E (ApoE) known for its involvement in Alzheimer’s disease (more prevalent in individuals with T21) and Kininogen 1 (KNG1)—implicated in the development of nuchal translucency, a marker for chromosomal abnormalities in T21. This evidence concerns the gene KNG1 and early-onset autosomal dominant Alzheimer disease.