The Unrecognized Mortality Burden of Genetic Disorders in Infancy.

To determine how deaths of infants with genetic diagnoses are described in national mortality statistics. We present a retrospective cohort study of mortality data, obtained from the National Death Index (NDI), and clinical data for 517 infants born from 2011 to 2017 who died before 1 year of age in the United States. Although 115 of 517 deceased infants (22%) had a confirmed diagnosis of a genetic disorder, only 61 of 115 deaths (53%) were attributed to , codes representing congenital anomalies or genetic disorders (Q00-Q99) as the underlying cause of death because of inconsistencies in death reporting. Infants with genetic diagnoses whose underlying causes of death were coded as Q00-Q99 were more likely to have chromosomal disorders than monogenic conditions (43/61 [70%] vs 18/61 [30%];  < .001), which reflects the need for improved accounting for monogenic disorders in mortality statistics. Genetic disorders, although a leading cause of infant mortality, are not accurately captured by vital statistics. . Expanded access to genetic testing and further clarity in death reporting are needed to describe properly the contribution of genetic disorders to infant mortality.