Aplasia or hypoplasia of the breasts and/or nipples (BNAH) is a rare condition. Several terms have been used to classify abnormal breast development including athelia, amazia, and amastia. BNAH is mostly part of syndromes including other congenital or ectodermal anomalies, such as limb-mammary syndrome[DS:H00640], scalp-ear-nipple syndrome [DS:H02691], or ectodermal dysplasias [DS:H02456]. Recently, it has been reported that mutations in PTPRF cause this disease. PTPRF encodes a receptor-type protein phosphatase that localizes to adherens junctions and may be involved in the regulation of epithelial cell-cell contacts, peptide growth factor signaling, and the canonical Wnt pathway.
