Transmembrane and coiled‐coil 2 (TMCC2) is an apolipoprotein E‐binding protein with an evolutionarily conserved interaction with the amyloid protein precursor family, mutation of whose Drosophila orthologue causes neurodegeneration with features of Alzheimer's disease (AD). This evidence concerns the gene TMCC2 and early-onset autosomal dominant Alzheimer disease.