This is HANDS DOWN the BEST resource for studying metabolic conditions! I am so grateful to the authors for making this, & having a free app & web version for the older addition available. I love it so much, I just bought the 5th edition book version, & am using this app to study while waiting for the book to arrive from the UK! I also bought a copy to give to the program director of my genetic counseling program, since I think it’s such a valuable resource to have available for future students. I LOVE how it briefly explains the metabolic pathway for a specific category of disease, before listing all the conditions within that category, with a summary of ALL pertinent details for each, including: age of onset, signs/symptoms, critical biochemical findings, testing, inheritance etc. This is a MUST HAVE resource for genetic counselors, GC students & medical geneticists. Thank you so much to the creators for this valuable resource!