Abstract
Renal cysts and diabetes syndrome (RCAD) is a rare disease caused by abnormalities in the HNF1B gene, which often leads to dysfunction in the renal, genital tracts, and pancreas. In this report, we present a rare case of a 27-year-old female with muscle mass loss who experienced a delayed diagnosis of RCAD. The patient had been misdiagnosed as "type 1 diabetes" for a long period. Her main clinical manifestations included muscle loss, renal magnesium loss, and an incomplete longitudinal uterus. Ultimately, the diagnosis of RCAD syndrome was confirmed through genetic testing. Reduction of muscle mass, although rarely reported, can progress to sarcopenia. Therefore, early intervention should be strongly emphasized. Furthermore, in future research, it is crucial to explore the mechanisms and relationships underlying these patients and their unusual manifestations.