Congenital microcephaly: Phenotypic features in a consecutive sample of newborn infants

Objective: We compared the prevalence of major and minor anomalies in a con secutive sample of newborn infants with congenital microcephaly with that a mong normocephalic infants. Study design: Head measurements from >19,000 liveborn infants at 1 hospital during the years 1991 and 1992 were reviewed. Infants whose head circumfer ence was in the lowest quartile (n = 850) were remeasured by research assis tants to identify all whose head circumference was 2 SD below the mean for gestational age; 106 infants with congenital microcephaly were identified. Infants with microcephaly (n = 65) and 294 infants in a control group were examined systematically for major malformations and minor physical features . Results: Four (6.2%) of the 65 infants examined either had a major malforma tion or were considered dysmorphic. One of the 4 had a specific multiple ma lformation syndrome, and 1 dysmorphic infant had a rare metabolic defect. O verall, the infants with microcephaly did not have a higher frequency of mi nor anomalies. However, there was a higher frequency of frontal bossing, sm all chin, and short nose with anteverted nares, which was associated with s mall body size rather than microcephaly. Conclusions: Congenital microcephaly is infrequently accompanied by major m alformations and occurs rarely as part of a recognizable syndrome.