I attended UCLA and University of Cambridge for my MD and PhD degrees and then trained as a pediatrician and neonatologist at Boston Children’s Hospital. I was a postdoctoral fellow in Andy McMahon’s lab at Harvard University. As a physician-scientist, I have investigated extensions of neuroscience that can impact our understanding of human neurological diseases, particularly cerebral palsy, multiple sclerosis and brain cancers. For over 15 years we have investigated the developmental genetics of the glial lineages of the brain and novel functions for astrocytes and oligodendrocytes. I helped establish the first “Neuro-NICU” in the USA at UCSF. This inter-disciplinary unit, focused on newborn neurological injuries, has improved standards of care and has facilitated basic and clinical research. I directed a first-in-man Phase I study of neural stem cell transplant into the human brain for leukodystrophy as an approach for demyelinating disorders. As a HHMI Investigator, I established a basic program of research in human neonatal brain development that has attracted support of an NINDS PO1. In 2016 I joined University of Cambridge as Head of Department of Paediatrics, where I have investigated application of whole genome sequencing in care of intensively ill children, supported by the UK National Institute for Health Research, Health Education England, Royal College of Paediatrics and Child Health, and the National Health Service (NHS). I am a Wellcome Trust Senior Investigator with a laboratory in the Cambridge Stem Cell Institute and Adjunct Professor of Pediatrics/Neonatology at UCSF, and I serve on the National Advisory Council Child Health and Development, National Institute of Child Health and Development.