[Sarcoidosis in a man and his identical twin sons].

Sarcoidosis is known to be a disease characterized by high familial aggregations. We reported on the genealogy of sarcoidosis in a man and his identical twin sons. The patient we encountered was a 49-year-old man admitted to our hospital because of abnormal chest X-ray findings observed during a medical checkup. Cervical and hilar lymph nodes were swollen on both sides, and lesions were observed in the right lung field. Biopsy specimens from cervical lymph nodes disclosed epithelioid cell granuloma without caseous necrosis. A diagnosis of sarcoidosis was made. The disease had also been diagnosed in the patient's identical twin sons 2 years earlier. They had been successfully treated and no recurrence has been observed. HLA typing disclosed that the father and his twin sons had identical A 33 (19), B 44 (12), DR 2, and DR 12 genes. This finding suggested that genetic factors are involved in the onset of this disease.