P816: TRANSIENT MONOSOMY 7 IN SAMD9/9L SYNDROMES: IS IT SAFE TO WATCH AND WAIT? - M. Erlacher; F. Andresen; A. Yoshimi; M. Sukova; J. Stary; B. de Moerloose; M. Dworzak; S. Polychronopoulou; G. Göhring; C. Kratz; J. van der Werff ten Bosch; M. Seidel; et al. (HemaSphere, 2022)