CC to At change at position 12,771, which substitutes Asn for a conserved Thr residue just upstream of RNP2 in the second RNA recognition motif.
Sxlf24,M1/Sxlf4 females show high levels of X chromosome nondisjunction. Recombination across the y-sn interval on the X chromosome is only 0.5% that of controls, recombination across the 2nd chromosome is only 5% that of controls and recombination across the 3rd chromosome is only 7% that of controls.