MODY5 is one of the less common forms of MODY (1–2%). It is a genetic disorder inherited through an autosomal dominant mutation or deletion of the hepatocyte nuclear factor-1beta gene.

MODY5 is associated with genital tract malformations such as hypoplasia of uterus, hypoplasia of vagina, bicornuate uterus, other uterine malformations, hypospadias and atresia of vas deferens. Moreover, moderate idiopathic hyperuricaemia, elevated liver function tests (ALT, GGTP) without jaundice and with normal ultrasound image of the liver, pancreatic atrophy and pyloric stenosis were found in some patients. Objective: Description of the maturity-onset diabetes of the young type 5 (MODY5), a rare type of diabetes.

A 30-year-old woman, with no family history of diseases, was repeatedly seen by various healthcare professionals because of her numerous non-specific symptoms: pain in the forehead, stomach pain, retrosternal pain, lower limbs pain, reduced right eye visual acuity, dizziness, photosensitivity, syncope, diarrhoea, nausea, weight loss, fatigue, action tremor of the whole body most prominent in the right upper limb and muscle weakness most notable in the morning. She was diagnosed with diabetes and was initiated on insulin therapy. Blood samples were taken for immunological and genetic investigations. Testing revealed the patient is heterozygous for mutation of deletion of the hepatocyte nuclear factor-1beta gene, that is MODY5 gene. The patient was switched to OHA therapy. The mutation of factor-1beta was not found in the patient’s family.

Ultrasound scanning of the abdomen revealed a 12 mm cyst with massive wall calcification in the right kidney and one cyst with solid component and three small, simple cysts in the central part of the left kidney. It also showed a 50 mm right ovarian cyst, bicornuate uterus and a vaginal fibroma. Skin lesions on the right shin were identified as necrobiosis lipoidica. Laboratory tests showed high urine pH and periodic electrolyte disturbances such as hypokalemia.

Differential diagnosis that includes monogenic forms of diabetes may lead to optimization of treatment and more accurate evaluation of prognosis for patients and their family members.