Answers to clues are placed horizontally in rows to reveal an answer written vertically. Unlike the familiar acrostic puzzle format, the final answer can be in any column.
1) The effect of Mustard on mixed-up blood in the heart
2) Pretty primitive as reflexes go
3) Brain nucleus with a bend toward appetite
4) Selective, akinetic—we can't say
5) Scintillating feature of migraine
6) Diagnosis takes time or Kveim
7) Can be a real pain in the butt ... and thigh
8) Baker's dozen pounds, different metric
Find in the vertical columns: Christmas never had enough of this. The puzzle grid is Table 1.
Answer: Factor IX
The answer grid is Table 2. Deficiency of factor IX causes Christmas disease, or hemophilia B. The original mutation was identified in 1952 by sequencing the DNA of a young boy named Stephen Christmas, who was found to be lacking this factor. Recombinant factor IX is used to treat Christmas disease, and a formulation is commercially available. (Source)
Holiday bonus clue: Find another holiday-related item (minus an “E”) in the vertical columns.