29 Prediction of Rh Genotypes from Phenotypes

Most Probable: (Rh positive patients)

1. D always on first chromosome
   1. Look for big letters;If pt. has both C and E, C goes on first chromosome and E goes on second chromosome. Never put both C and E on same chromosome for most probable genotype.
   2. If pt. only has C; put it on first chromosome
   3. If pt. only has E; put it on first chromosome
2. Look at little letters;
   1. If pt. has both c and e, e goes on first chromosome and c goes on second chromosome
   2. If pt. only has e (no E) put on both chromosomes
   3. If pt. only has c (no C) put on both chromosomes
3. If you have a big letter on the second chromosome, then the “D” is a big D. If you don’t have a big letter then the “D” is most likely a little d.

Second most Probable

Switch D to d or d to D on the second chromosome

Third most Probable

Switch the big letters from the first to second chromosome and vice versa

Always have a little d on the second chromosome

Fourth most Probable

Put all big letters on the first chromosome

The little d is still on the second chromosome

Fifth most Probable

Change the little d to a big D on the second chromosome

Sixth most Probable

Switch the C and E to the second chromosome and the c and e to the first chromosome

Change the big D on the second chromosome to a little d