Molecular and clinical description of a girl with a 46,X,t(Y;4)(q11.2;p16)/ 45,X,der(4)t(Y;4)(q11.2;p16) karyotype and a small cryptic 4p subtelomeric deletion

We report on a 13-year-old female with short stature, minimal axillary and pubic hair, no breast development, absence of uterus and ovaries, with the following karyotype on lymphocyte cultures: 46,X,t(Y;4)(q11.2;p16) [40]/45,X, der(4)t(Y;4)(q11.2;p16)[10]. Loss of the small derivative Y chromosome in 20% of the cells was also confirmed in skin fibroblast cultures. FISH analyses using Y centromere, SRY, subtelomere XpYp/XqYq, Y and 4 painting probes, confirmed the cytogenetic findings. High-resolution STS analyses using 40 markers covering the Y chromosome did not identify any deletion on the Y. However, de novo absence of the 4p subtelomeric region was noted by FISH, although this deletion was not revealed by Array-CGH at 1 Mb resolution, the last array clone being 0.35 or 1 Mb distal to the 4p FISH probe. The female phenotype of this patient must be due to the loss of the derivative Y chromosomes in some of her cells, especially the gonads, while the 4p subtelomeric deletion does not seem to contribute to her phenotype.