phocomelia

Phocomelia is a rare congenital limb malformation in which the proximal limb segments fail to develop, resulting in severely shortened arms or legs. The hands or feet may be attached close to the trunk, while the distal segments can be relatively preserved. The condition can be isolated or occur as part of a broader syndrome such as Nager or Roberts.

Most cases are sporadic. The best known cause is prenatal exposure to the sedative thalidomide during weeks 4–7 of gestation, which produced thousands of phocomelia births in the late 1950s and early 1960s. Other causes include vascular disruption in limb buds, amniotic band sequence, and, less commonly, genetic mutations associated with specific syndromes.

Diagnosis is established by prenatal ultrasound and confirmed by postnatal radiographs showing absence or hypoplasia of proximal bones. Phocomelia is distinguished from meromelia and amelia by the pattern of limb reduction and preserved distal elements.

Management requires a multidisciplinary approach, including orthopedic and plastic surgeons, physical and occupational therapy, prosthetic fitting, and psychosocial support. Interventions aim to maximize function, independence, and quality of life, and may involve staged reconstructive procedures.

Epidemiology and history: Phocomelia is very rare; after thalidomide regulation, incidence declined. Contemporary cases occur worldwide, sometimes in association with genetic syndromes. The thalidomide disaster significantly influenced drug safety regulations and birth defect surveillance.