The Largest Paracentric Inversion, the Highest Rate of Recombinant Spermatozoa. Case Report: 46,XY, inv(2)(q21.2q37.3) and Literature Review.

Carriers of inversions involving euchromatic regions are at risk of having unbalanced offspring due to meiotic crossover. In carriers, recombination can occur during gametogenesis and cause genetically unbalanced sperm and subsequently unbalanced embryos. Here we present segregation analysis results of an infertile male with 46,XY,inv(2) (q21.2q37.3) using fluorescent in situ hybridization (FISH) on sperm cells. This is the largest paracentric inversion (PAI) reported so far in a meiotic segregation analysis study. Sperm FISH revealed 28.0% recombinant spermatozoa rate for chromo-some 2, which was the highest rate in PAI carriers in the literature. Our results indicate a clear correlation between the size of the inverted segment and the frequency of the recombinant spermatozoa. The results of the FISH analysis with the information of unbalanced spermatozoa rate can provide accurate counseling on the genetic risk of infertility.