GRIP1 and Fraser syndrome: Fraser syndrome is caused by mutations in the FRAS1 (4q21.21), FREM2 (Fras1-related extracellular matrix gene 2) (13q13.3), and GRIP1 (glutamate-receptor-interacting protein 1) (12q14.3) genes, coding for extracellular matrix proteins essential for the adhesion between the basement membrane of the epidermis and connective tissues of the dermic layer during embryological development.