As a Clinical, Biochemical and Molecular Geneticist, Dr. Phillips has diagnosed, treated, and cared for children and adults with many genetic diseases, including congenital malformations, chromosomal, Mendelian, and metabolic disorders. He has been the principal investigator (PI) on clinical trials to treat Achondroplasia, Argininemia, Fatty Acid Oxidative Disorders, Methylmalonic Acidemia, and Phenylketonuria. These clinical trial studies contributed significant data that led to the FDA approval of four drugs to treat genetic disorders. As a clinician, Dr. Phillips contributes to the efforts of the Division of Medical Genetics and Genomic Medicine which currently sees approximately 5,000 total genetic cases annually.

Dr. Phillips has been a Subject Editor for the Online Mendelian Inheritance in Man (OMIM) database (https://www.omim.org). He has been a Co-Director of and lecturer in the American College of Medical Genetics, Genetics Review Course from 2005-present. He has also been a lecturer in the Annual McKusick Short Course in Medical and Experimental Mammalian Genetics, Jackson Lab, Bar Harbor, Maine from 1977 to present.

Dr. Phillips' past research focused on Mendelian disorders that have heterogeneous causes, reduced penetrance, and variable expression (Familial Growth Hormone Deficiency, Hereditable Pulmonary Arterial Hypertension, and Familial Pulmonary Fibrosis), as well as undiagnosed and many rare genetic diseases. He has shared in the discovery of multiple genetic disorders, the mechanisms underlying many, as well as the treatment of others. He is currently a Co-PI of the Vanderbilt Center for Undiagnosed Diseases (VCUD), a segment of the NIH Undiagnosed Disease Network (UDN). He also sees patients referred to the new Vanderbilt Undiagnosed Diseases Program (VUDP). In a recent review, it was discovered that 33% of our UDN diagnoses were not solved exclusively by exome sequencing (ES), and several methods were needed to detect and/or confirm the functional effects of the DNA variants that were missed by ES, and in some cases by genome sequencing.