Acquired partial lipodystrophy (APLD) is characterized clinically by the gradual onset of bilaterally symmetrical loss of subcutaneous fat from the face, neck, upper extremities, thorax, and abdomen, in the 'cephalocaudal' sequence, sparing the lower extremities. A large group of patients (83%) with acquired partial lipodystrophy have low serum levels of complement component C3 due to the presence of C3 nephritic factor, an IgG antibody that causes continuous activation of the alternative complement pathway and consumption of serum C3. About 22% of patients with this acquired complement defect develop membranoproliferative glomerulonephritis. Some individuals may also show an increased risk of infection (Misra et al., 2004). Acquired partial lipodystrophy is not inherited in a classic mendelian pattern; it rather represents a phenotype with a complex etiology. Affected individuals may have genetic susceptibility factors that require the additional presence of environmental factors or acquired disorders to be expressed (summary by Hegele et al., 2006). Most cases are sporadic, family history is negative, and females are more often affected than males (ratio, 4:1) (summary by Misra et al., 2004). See 608709 for a subtype of APLD not associated with low complement C3 or renal disease.

An inherited susceptibility or predisposition to developing acquired partial lipodystrophy.