Cognitive development. Calendar age is depicted on the horizontal axis, with developmental age on the vertical axis. The continuous and dashed black lines represent the reference curves (+2 SD, 0 SD, and −2 SD). (A) Subdivided by the cognitive status (DQ/IQ) pre-HCT; median or higher (≥85) vs lower than median (<85). (B) Subdivided by the age at HCT; lower than median (<16 months) and median or higher (≥16 months).