Hypoplasien

Hypoplasien, the plural form of hypoplasia, denotes underdevelopment or incomplete growth of an organ or tissue due to insufficient cell production during development. It is typically present at birth and may affect a single structure or multiple systems. Hypoplasia is contrasted with aplasia (complete absence) and with atrophy (reversible size reduction after normal development). The term is used across medical disciplines, including dentistry, cardiology, and nephrology.

Examples include enamel hypoplasia (deficient enamel formation with pits or grooves), pulmonary hypoplasia (underdeveloped lungs), renal hypoplasia (small kidneys with reduced nephrons), and limb hypoplasia (incomplete limb formation). Some congenital heart defects, such as hypoplastic left heart syndrome, involve underdevelopment of cardiac chambers. Hypoplasia can affect a tissue’s size, structure, or organization without complete absence.

Causes include genetic mutations that disrupt organogenesis, teratogenic exposures during pregnancy, vascular compromise that reduces fetal blood flow, and nutritional deficiencies. The exact mechanism varies by tissue. Hypoplasia can be isolated or occur as part of broader syndromes. Distinguishing hypoplasia from aplasia or dysplasia relies on clinical, imaging, and histological findings.

Diagnosis relies on imaging, such as ultrasound or MRI, and is often confirmed by histology or postnatal assessment. Treatment targets the affected organ and may involve surgical reconstruction, medical management, prosthetics, or supportive care. In dental cases, preventive care and restorative procedures mitigate functional and aesthetic effects. The prognosis depends on the organ involved and the severity of underdevelopment.