Related disorders in the same disease spectrum as HDLS include Nasu-Hakola disease (polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy), and a type of leukodystrophy with pigment-filled macrophages called pigmentary orthochromatic leukodystrophy (POLD) [REF].
Nasu-Hakola disease appears to be caused by mutations in the TYRO protein tyrosine kinase-binding protein (TYROBP - also known as DAP12) or the triggering receptor expressed on myeloid cells 2 (TREM2) protein.