While the most abundant basement membrane laminin chain (Lamc1) was unaltered in both abundance (Fig. 6d) and solubility (Fig. 6g), serving as a control for overall integrity of the basement membrane and the quality of our data, the basement membrane-associated trimeric Fraser Syndrome complex (consisting of Fras1, Frem1, and Frem2) was downregulated (Fig. 6e) and more soluble (Fig. 6h) in old age. This evidence concerns the gene FREM2 and Down syndrome.