[Clinical and cytogenetic diagnosis of Martin-Bell syndrome]

A total of 368 patients aged 1 year 11 months to 35 years with oligophrenia were examined cytogenetically. Out of 58 boys with a typical disease picture, the fragile X chromosome (fra-X) was revealed in 57. In all the cases, the syndrome could be diagnosed clinically before chromosomal analysis was made. In a group of children with undifferentiated oligophrenia including those with the sex-linked inheritance type, fra-X was not discovered. Besides, the fragile X chromosome was revealed in 4 girls. Of these, 3 were probands' sisters and one case was sporadic. The girls manifested both symptomatology typical for Martin-Bell syndrome and nonspecific mental retardation. Another 55 probands' relatives were examined clinically and cytogenetically. The fra-X was discovered in 9 mothers of the patients. The mean IQ in the women with the revealed fragile X chromosome was much lower than the mean IQ of all the women, mothers of the sick children. It is concluded that in spite of a wide range of the variability of somatic and psychopathological disorders in patients with Martin-Bell syndrome, the possibility of the clinical diagnosis of the disease without making cytogenetic studies attains as much as almost 100%. Symptoms, specific for the clinical diagnosis of the disease were distinguished.