The identification of a novel homozygous FBLN5:c.53del frameshift variant in cutis laxa type 1A and a heterozygous ATM:c.4828dup frameshift variant in ataxia telangiectasia demonstrates the value of whole genome sequencing followed by Sanger confirmation in clarifying atypical and overlapping phenotypes. This evidence concerns the gene ATM and ataxia telangiectasia.