Ribonucleases are ubiquitous enzymes involved in RNA metabolism and are classified in several families on the basis of their structural, catalytic and biological properties. RNase 13 (ribonuclease, RNase A family, 13), is a 156 amino acid secreted protein encoded by a gene that maps to human chromosome 14q11.2. Chromosome 14 houses over 700 genes and comprises nearly 3.5% of the human genome. Chromosome 14 encodes the presinilin 1 (PSEN1) gene, which is one of the three key genes associated with the development of Alzheimer's disease (AD). The SERPINA1 gene is also located on chromosome 14 and, when defective, leads to the genetic disorder (alpha)1-antitrypsin deficiency, which is characterized by severe lung complications and liver dysfunction.