Rationale: The karyotype 49,XXXXY is a rare form of Klinefelter syndrome usually presenting with ambiguous genitalia, facial dysmorphism, mental retardation, and a combination of cardiac, skeletal, and other malformations.
Patient concerns: We describe a 19-year-old man, whose chromosomal analysis of peripheral blood revealed a karyotype of 49,XXXXY. His mental development and motor ability were significantly delayed. At the age of 19, he had failed to develop secondary sexual characteristics. His random blood glucose level was 19.61 mmol/L, and he showed dry mouth, polydipsia, and polyuria. He had a characteristic facial appearance with prognathism, widened nasal bridge, and strabismus. His bilateral elbow rotation was limited. He had atrophic testes with micropenis. Ophthalmic examination revealed a polar cataract in both eyes.
Diagnosis: He was diagnosed with Klinefelter syndrome associated with cleft palate, hypothyroidism, cataracts, diabetes, and other anomalies.
Interventions: After the initial diagnosis, the patient received intensive insulin therapy to correct hyperglycemia, and he received calcium and vitamin D supplements. The patient also received testosterone and thyroid hormone replacement therapy for primary hypogonadism.
Outcomes: The patient was discharged 12 days after receiving treatment; meanwhile, there were no clinical symptoms of dry mouth, polyuria and polyuria, and his blood glucose level was controlled.
Lessons: The combination of cleft palate, hypothyroidism, cataracts, diabetes, and osteoporosis in 49,XXXXY syndrome has not yet been reported. Early treatment and appropriate care can significantly improve the patient's quality of life and prevent serious consequences.