A 5-day-old male child presenting some features of Wolf syndrome is studied. The analysis of his karyotype by usual techniques showed a ring chromosome of B group. This chromosome was presnt in most of the cells examined. By GTG banding it was identified as a No.4 chromosome, the karyotype being: 46,XY,r(4),(p15 leads to q35). The analysis was completed by familial cytogenetic and dermatoglyphic studies.