Subtype of insulin-dependent diabetes mellitus (IDDM) in Japan: slowly progressive IDDM--the clinical characteristics and pathogenesis of the syndrome.

A prospective observation on the natural history of beta-cell function in islet cell antibody (ICA)-positive NIDDM disclosed characteristic findings of slowly progressive IDDM distinct from those of acute onset IDDM. The characteristic features includes: (1) late onset; (2) slow progression of beta-cell failure over several years with persistently positive low-titer ICA; (3) incomplete beta-cell loss; (4) frequent involvement of exocrine pancreas; (5) higher family history of NIDDM; and (6) association with some genetic predisposition including HLA-DQA1*0301-DQB1*0401 and/or mitochondrial gene mutation at nucleotide pair 3243.