Absence of the superior labial frenulum is reported in 88% of 17 consecutive cases of holoprosencephaly examined at St Christopher’s Hospital for Children, Philadelphia, PA. Brain imaging is recommended in children with this anomaly. Patients with midline facial abnormalities such as hypotelorism, smooth philtrum, or single central incisor should be examined for absent frenulum. 
COMMENT. Absence of the superior labial frenulum may be added to the spectrum of midline anomalies characteristic of the holoprosencephaly sequence.