Relationship between head circumference and height in normal adults and in the nevoid basal cell carcinoma syndrome and neurofibromatosis type I.

Occipitofrontal circumference (OFC) was strongly correlated with height in 72 normal Caucasian men (r = 0.28, P = 0.018) and 78 women (r = 0.53, P less than 0.0001). OFC:height ratios were approximately normally distributed in each sex with a mean of 0.326 (standard deviation [sd] = 0.0139) in males and 0.335 (sd = 0.0177) in females. Relative macrocephaly (an OFC greater than the 95th centile for height) was seen in seven of nine probands with the nevoid basal cell carcinoma syndrome (NBCC), eight of 32 non-probands with NBCC, three of four neurofibromatosis type 1 (NF1) probands, and six of nine non-probands with NF1. Thirty-one percent of the non-proband NBCC cases had OFC less than the 50th centile for height, while none of the NF1 cases had this finding. Head size appears to be related to proband status in NBCC, while the evidence suggests that NF1 is a true macrocephaly syndrome. Objective detection of relative abnormalities in head size may aid in syndrome delineation and diagnosis.