[Familial Yqs chromosome in 4 generations].

A structural aberration of the Y chromosome (Yqs) was identified in a 4-year-old child who visited a physician for right unilateral cryptorchidism. The structure of this chromosome was determined through bands C, G and NOR. The family cytogenetic study allowed for the detection of the Yqs in up to four generations. A comparison is made of the different phenotypes associated with this marker in the medical literature, concluding that this is probably due to another polymorphism of the Y chromosome.