latent autoimmune diabetes of adults (LADA)

Last reviewed 03/2021

• a subgroup of patients diagnosed earlier as type 2 diabetes (around 12%) (1) has circulating autoantibodies
  • circulating autoantibodies are to islet cell cytoplasmatic antigens (ICA) and more frequently to glutamic acid decarboxilase (GAD, GADab) (2)
    
    
• patients were reported earlier as type 1 diabetes, but according to the WHO Classification of diabetes mellitus it is called now Latent Autoimmune Diabetes in Adults (LADA) (3 and 4)
  • LADA could be a part of the type 2 diabetes since its onset is in the adulthood,
    • LADA shows some characteristics of type 2 diabetes, which is a heterogenous disease that results from a combination of abnormalities in both insulin secretion and insulin action
  • LADA cases are usually with genuine insulin deficiency, many are non-obese with a beta-cell secretory defect (3). This compares with other cases of type 2 diabetes where hyperinsulinaemia is a characteristic feature
  • in consideration of the genetic factors influencing the development of LADA (5):
    • the most important genetic risk factors for LADA is heterozygosity for DR3-DQ2/DR4-DQ8 followed by heterozygosity for MICA5.0/5.1, and finally to some extent homozygosity for DR3-DQ2
    • DR15-DQ6 is a protective factor for type 1 diabetes and to some extent for LADA
      
      
• some alternate the terms LADA and type 1.5 diabetes (6)
  • people diagnosed with LADA are usually over age 30

Reference:

1. M. Pietropaolo et al.Evidence of Islet cell autoimmunitiy in elderly patients with Type 2 diabetes. Diabetes 49 (2000): 32-38.
2. T. Tuomi et al.Clinical and genetic characteristics of type 2 diabetes with and without GAD antibodies. Diabetes 48 (1999): 150–157.
3. P.Z. Zimmet et al.atent autoimmune diabetes mellitus in adults (LADA): the role of autoantibodies to glutamic acid decarboxilase in diagnosis and prediction of insulin dependency. Diabetic Med. 11 (1994):299–303.
4. for the WHO consultation, K.G.M.M. Alberti and P.Z. Zimmet , Definition, diagnosis and classification of diabetes mellitus and its complications. Part 1: diagnosis and classification of diabetes mellitus. Provisional Report of a WHO consultation. Diabetic Med. 15 1998 (1998), pp. 539–553.
5. Torn C et al. Heterozygosity for MICA5.0/MICA5.1 and HLA-DR3-DQ2/DR4-DQ8 are independent genetic risk factors for latent autoimmune diabetes. Human Immunology (2003); 64 (9): 902-909.
6. "Latent autoimmune diabetes". Mayo Clinic. Retrieved September 28th, 2016.