Newborn tandem mass spectroscopy screening for adenosine deaminase deficiency.

BACKGROUND

Newborn screening (NBS) by means of T cell receptor excision circles (TREC) is now universal in the United States, Puerto Rico, and the Navajo Nation as a strategy to identify severe combined immunodeficiency (SCID) in newborns. Owing to the characteristics of adenosine deaminase (ADA) deficiency, a small but important number of cases can be missed by this screening.

OBJECTIVE

To evaluate the results of the first year statewide NBS for ADA by means of dried blood spot NBS.

METHODS

On October 7, 2019, the state of Michigan began screening newborn dried blood spots for ADA deficiency by means of the Neobase-2 tandem mass spectroscopy (TMS) kit. We report 1 known case of ADA deficiency in the 18 months before screening. We then reviewed the results of the first 2 years of TMS ADA screening in Michigan.

RESULTS

There was 1 patient with ADA deficiency known to our centers in the 18 months before initiation of TMS ADA screening; this patient died of complications of their disease. In the first 2 years of TMS ADA NBS, 206,321 infants were screened, and 2 patients had positive ADA screen results. Both patients had ADA deficiency confirmed through biochemical and genetic testing. One patient identified also had a positive TREC screen and was confirmed to have ADA-SCID.

CONCLUSION

In our first 2 years, TMS NBS for ADA deficiency identified 2 patients with ADA deficiency at negligible cost, including 1 patient who would not have been identified by TREC NBS. This report provides initial evidence of the value of specific NBS for ADA deficiency.