The leucine-rich (LRR) repeat is a 20-30 amino acid motif that forms a hydrophobic a/∫ horseshoe fold, allowing it to accommodate several leucine residues within a tightly packed core. All LRR repeats contain a variable segment and a highly conserved segment, the latter of which accounts for 11 or 12 residues of the entire LRR motif. SLITRK5 (SLIT and NTRK-like family, member 5), also known as LRRC11 (leucine-rich repeat-containing protein 11), is a 958 amino acid single-pass type I membrane protein that contains 16 LRR repeats and belongs to the SLITRK family. Expressed at high levels in the cerebral cortex, but also present in areas of the spinal cord and medulla, SLITRK5 functions to suppress neurite outgrowth, thereby playing a regulatory role in neuronal function. The gene encoding SLITRK5 maps to human chromosome 13, which houses over 400 genes, such as BRCA2 and RB1, and comprises nearly 4% of the human genome. Trisomy 13, also known as Patau syndrome, is deadly and the few who survive past one year suffer from permanent neurologic defects, difficulty eating and vulnerability to serious respiratory infections.