Rabson-Mendenhall Syndrome: Analysis of the Clinical Characteristics and Gene Mutations in 42 Patients.

Aims: Rabson-Mendenhall syndrome (RMS) is a rare autosomal, recessive disorder characterized by severe insulin resistance due to mutations in the insulin receptor (INSR) gene. This study aims to analyze the clinical features and gene mutations in RMS, which have not been extensively studied.

Methods: PubMed, Embase, the China National Knowledge Infrastructure, and Wanfang were searched for "Rabson-Mendenhall syndrome" or "Black acanthosis hirsutism insulin resistance syndrome."

Results: A total of 42 cases from 33 articles were included. The body mass index ranged from 18.50 to 20.00 kg/m with an average of 16.00 kg/m. There were no overweight (25.00∼29.90 kg/m) or obese (≥30.00 kg/m) patients. Acanthosis was present in 29 cases (29/42, 69.05%); growth retardation in 25 cases (25/42, 59.52%); dental anomalies including absence of teeth, crowding, and malocclusion in 23 cases (23/42, 54.76%); and hirsutism in 17 cases (17/42, 40.48%). The average glycosylated hemoglobin was 9.35%, and the average fasting blood-glucose was 8.44 mmol/L; the mean fasting insulin was 349.96 μIU/mL, and the average fasting C-peptide was 6.00 ng/mL. Diabetes was reported in 25 cases (25/33, 75.76%) all of which were diagnosed before 23 years old. All 42 patients had recorded gene mutations, with 22 patients (22/42, 52.38%) having ≥ 2 mutations and 20 cases (20/42, 47.62%) having only 1 mutation. No statistical differences were found in clinical features and laboratory parameters between patients with different mutations.

Conclusion: The study indicates that RMS should be considered in young patients with hyperinsulinemia, hyperglycemia with low weight, acanthosis nigricans, growth retardation, dental anomalies, and hirsutism.