A case of Type-1 diabetes mellitus formerly diagnosed as maturity-onset diabetes of the young (MODY) carrying suggestive MODY3 gene

Abstract

It is sometimes difficult to determine the type of diabetes in lean young Japanese patients who require insulin treatment just after diagnosis of diabetes. Insulin-requiring diabetes with nonabrupt onset of diabetes, presence of family history of diabetes, and absence of the islet cell antibody (ICA) are not compatible with Type-1 diabetes or insulin-dependent diabetes (IDDM) but may be compatible with Type-2 diabetes or non-insulin dependent diabetes (NIDDM). Two third of diabetic patients diagnosed before the age of 30 are NIDDM in Japan [1]. Maturity-onset diabetes of the young (MODY), characterized by an early age of onset, usually before 25 years old, and autosomal dominant inheritance, account for 5% of NIDDM patients in Japan [2]. Recent linkage studies have revealed the MODY genes to be localized on chromosome 20 (MODY1, hepatocyte nuclear factor-4a gene [3]), chromosome 7 (MODY2, glucokinase (GCK) gene), and chromosome 12 (MODY3, hepatocyte nuclear factor-1a gene [4]). Here, we present a MODY female patient who was suggested to link the MODY3 locus in linkage study [5], but later was found to be positive for anti-glutamic acid decarboxylase (GAD) antibody. A 24-year-old woman (TK) was first admitted to our Diabetes Center 5 years ago, because of thirst, polydipsia, polyuria and body weight loss (52“47 kg/5 months). She had been well until 5 * Corresponding author. Tel.: +81 3 33538111, ext. 27011; fax: +81 3 33581941.