BTK and hydrops fetalis: In GS, the combinations IGHV10/34-IGHD1 (s, BTA7)-IGHJ1 and IGHV10/34-IGHD4 (s, BTA8)-IGHJ1 were preferred (2.29%), whereas in HF, IGHV10/34-IGHD3 (s, BTA7)-IGHJ1 was found most often (1.26%).