New advancements in magnetic resonance fingerprinting (MRF) allow more accurate quantification of tissue characteristics and its components using multi-component dictionaries. Recently, a multi-component method for mapping Myelin-Water fraction (MWF) was suggested and validated in healthy children. Here, we studied a cohort with different disorders including hypo- or de- myelinization, Creatine Deficiency Syndrome and brain malformations. We reconstruct MWF maps using tailored dictionaries and estimate fractional myelin values in the splenium of corpus callosum. We observed that myelinization plateaus at around 30 months from birth, while in patients with white matter disorders the process is distorted.