He contributed to the discovery of two genes related to Branchio-oto-renal syndrome (BOR) and Autosomal Dominant Polycystic Kidney Disease (ADPKD2).

Later, he served as the principal investigator on a National Institutes of Health-funded research grant, which led to the discovery of two genes viz.

[1] He was also involved in the discovery of an additional gene linked to branchio-otic (BO) type syndrome, located on chromosome 1q31.

[2] His contributions are documented in OMIM, (Online Mendelian Inheritance in Man), a comprehensive catalog of human gene discoveries and genetic disorders.

[3][4][5] Kumar, whose efforts are also associated with the Native-American communities, serves at the Munroe Myer Institute at the University of Nebraska Medical Center.