Lipodystrophies are an immense group of genetic or acquired metabolic disorders that are characterized by varying degrees of body fat loss and in some instances localized accumulation of subcutaneous fat.
Lipodystrophies are often tightly linked with profound metabolic complications; this strong bond emphasizes and reinforces the significance of adipose tissue as a dynamic endocrine organ. The extent of fat loss determines the severity of associated metabolic complications such as
diabetes mellitus,
hypertriglyceridemia and hepatic steatosis. The
lipodystrophies can be divided into generalized, partial or local, depending on the degree and locality of the observable fat loss; moreover, the generalized and partial divisions can be partitioned further into inherited or acquired forms. The major genetic factors in the generalized forms of the
lipodystrophies, particularly
Congenital generalized lipodystrophy (CGL)-
Berardinelli-Seip syndrome, are the AGPAT2, BSCL2,
caveolin 1 (CAV1) and polymerase-I-and-transcriptrelease factor (PTRF) genes. In the acquired forms, genes such as LMNA, PPARG, CIDEC (cell-death-inducing DNA fragmentation
factor a-like effector c) and PLIN1 are heavily involved in
familial partial lipodystrophy (FPLD) type 2 (also known as the Dunnigan-Variety) and WRN along with RECQL5 in
Werner Syndrome (WS). Autoimmune causes are particularly noted in
acquired partial lipodystrophy (APL)-
Barraquer-Simons syndrome and in AGL-Lawrence syndrome;
panniculitis has been shown to have a substantial role in the former as well as in other forms of localized
lipodystrophies. Patients with human immunodeficiency virus (HIV) exposed to
protease inhibitors,
nucleoside reverse transcriptase inhibitors (NRTIs) (for example,
zidovudine and
stavudine) or non-
nucleoside reverse transcriptase inhibitors (NNRTIs) (for example,
efavirenz) while undergoing
Highly Active Antiretroviral Therapy (
HAART) have led to the current most-prevalent form of the
lipodystrophies:
lipodystrophy in HIV-infected patients (LD-HIV) and
HAART-associated
lipodystrophy syndrome (HALS).