Screening for autosomal aberrations.
A method of screening for autosomal aberrations is important as an indication for chromosome analysis such as that used in sex-chromatin examination for sex chromosome aberrations. In our clinic, malformed patients with mental retardation and abnormal dermatoglyphic patterns are strong suspects for autosomal aberrations. Abnormal dermatoglyphic patterns are separated into two categories: (1) Absolutely abnormal--radial loop of 1st finger, radial loop of 4th finger, radial loop of 5th finger, arch over 6 fingers, arch tibial, loop tibial, and arch fibular; (2) Borderline abnormalities--high axial triradius (t' and t"), simian crease, interdigital loop, and single crease of 5th finger. Of 416 cases showing malformation, retardation, and abnormal dermatoglyphics, 308 had autosomal aberrations, while 108 had normal karyotypes. In the group with autosomal aberrations, 279 patients (90.6%) had absolutely abnormal dermatoglyphics. In the group with normal karyotypes only 8 patients (7.4%) had absolutely normal dermatoglyphics, while most had abnormal dermatoglyphics in the borderline category. These clinical manifestations: absolutely abnormal dermatoglyphics, mental retardation, and malformations are therefore very useful in screening for autosomal aberrations.