Frequency of deletion of short arm satellites in acrocentric chromosomes.

The frequency of deletion of short arm satellites has been examined in various populations. Four out of 2509 males in psychiatric institutions and prisons had Dps- or Gps- (1·6 per 1000), and five out of 6187 persons in the general population had Dps- or Gps- (0·8 per 1000). The difference is not significant. The segregation rate of the chromosome with lack of short arm satellite material did not deviate from unity in the few families where such calculations were possible. There was no increase in abortions or non-disjunction in the families with an acrocentric chromosome lacking short arm satellite material. The study indicates that the frequency of Dps- and Gps- in the population is between 0·5 and 1·0 per 1000 and that the lack of short arm satellite material is without any deleterious effect on phenotype.