evidence: Persons using assistive technology might not be able to fully access information in this file. For assistance, please send e-mail to: mmwrq@cdc.gov. Type 508 Accommodation and the title of the report in the subject line of e-mail. [...] In all four states, lower prevalences were observed consistently for the youngest and oldest groups, compared with the middle two age groups. The lower prevalences for males aged 5--9 years (born during 1998--2002) might reflect diagnostic delays previously reported by MD STARnet (4). The case classification used by MD STARnet rigorously defines probable or definite cases, but might not identify all cases of DBMD. This might be especially true for males aged 20--24 years (born during 1983--1987) because widespread use of genetic diagnostic tests did not begin until the early 1990s. Additionally, this group has the lowest survival. [...] Users are referred to the electronic PDF version (http://www.cdc.gov/mmwr)