Breasts and/or Nipples, Aplasia or Hypoplasia of, 2, is also known as bnah2. An important gene associated with Breasts and/or Nipples, Aplasia or Hypoplasia of, 2 is PTPRF (Protein Tyrosine Phosphatase Receptor Type F). Affiliated tissues include breast, and related phenotypes are smooth philtrum and anteverted nares