Inclusion Criteria: Individuals of all ages diagnosed with SPLIS based on bi-allelic pathogenic variants of SGPL1, including children and neonates, as well as family members or caregivers, healthy volunteers and individuals with other sphingolipidoses.  Exclusion Criteria: the investigators will not include:  prisoners pregnant women  healthy volunteers with:  diabetes, infection, fever, known HIV/AIDS, cardiac disease or anemia.