Thirteen children in MADDSP were identified as having possible metabolic disorders.
For the child reported with tyrosinuria, no confirmatory information was available in the MADDSP records, and no additional information about this child was located by searching records of the genetics programs in the area.
However, only two children from these birth cohorts were identified in MADDSP as having MR associated with one of these underlying metabolic disorders.
Therefore, treated children may not meet the MADDSP case definition for MR but may still have some cognitive impairment.
During 1981-1989, MACDP and MADDSP combined identified 92 children with possible FAS: MACDP uniquely identified 50 (54%) of these possible cases; MADDSP uniquely identified 31 (34%); and both registries identified 11 (12%).
children identified by MACDP may have had an increased likelihood of being identified by MADDSP because a child already identified as having FAS probably is more likely to have cognitive evaluations and to enter special education).
For this period, MADDSP identified 413 children (283 in 1991, 288 in 1992, and 293 in 1993) who met the surveillance case definition for hearing impairment.
Because MADDSP focuses primarily on children with serious bilateral hearing impairment, these findings probably underestimate the actual magnitude of delayed diagnosis.
Second, the age at earliest diagnosis used by MADDSP refers to the age when the child's hearing loss first met the MADDSP case definition; this age may not be the earliest time when a less serious loss was noticed.
Children reported in MADDSP were born during 1981-1990, before the issuance of recommendations for universal newborn hearing screening.
Although the MADDSP
methodology included a comprehensive review of records from multiple sources in a population-based setting, the cause was defined as "other than postnatal" when etiologic information was confusing, conflicting, or missing.