Insulin-Resistance Syndrome Type B

A rare genetic disease that belongs to the group of extreme insulin-resistance syndromes and is due to autoantibodies directed against insulin receptor.

Epidemiology

Insulin-resistance syndrome type B is a rare disorder that mainly affects middle-aged adults, predominantly females. The prevalence is unknown.

Clinical description

The disease may occur in the context of other autoimmune phenomena or well-characterized autoimmune diseases (mainly systemic lupus erythematosus). The onset of the disease is usually characterized by the appearance of a rapidly progressive, severely insulin-resistant diabetes with acanthosis nigricans (the typical skin lesion associated with insulin resistance), weight loss, and hirsutism in females. Hypoglycemia can occur during the course of the disease, or, more rarely, can be the only metabolic manifestation, and may be extremely severe. Unlike most insulin resistance syndromes, type B insulin resistance is not associated with hypertriglyceridemia.

Etiology

The syndrome is associated with the presence of serum auto-antibodies directed against the insulin receptor.

Diagnostic methods

The diagnosis is based on the clinical picture, results of laboratory tests, and on detection of anti-insulin receptor auto-antibodies in the serum.

Differential diagnosis

The differential diagnosis include other insulin resistance syndromes and/or hypoglycemia due to other causes.

Management and treatment

Immunosuppressive combination therapies including rituximab were shown effective to induce remission in most cases and should be followed by maintenance immunosuppressive therapy. Non specific therapies should be associated to reverse the hypercatabolic state and treat hyperglycemia (large amount of insulin) and/or hypoglycemia (diet, adaptation of insulin therapy, steroids).

Prognosis

Prognosis depends on the course of the underlying autoimmune disease, and is unfavorable in cases with hypoglycemia (reported to lead to death in 50% of cases).