Face shape of unaffected parents with cleft affected offspring: combining three-dimensional surface imaging and geometric morphometrics.
OBJECTIVE
Various lines of evidence suggest that face shape may be a predisposing factor for non-syndromic cleft lip with or without cleft palate (CL/P). In the present study, 3D surface imaging and statistical shape analysis were used to evaluate face shape differences between the unaffected (non-cleft) parents of individuals with CL / P and unrelated controls.


METHODS
Sixteen facial landmarks were collected from 3D captures of 80 unaffected parents and 80 matched controls. Prior to analysis, each unaffected parent was assigned to a subgroup on the basis of prior family history (positive or negative). A geometric morphometric approach was utilized to scale and superimpose the landmark coordinate data (Procrustes analysis), test for omnibus group differences in face shape, and uncover specific modes of shape variation capable of discriminating unaffected parents from controls.


RESULTS
Significant disparity in face shape was observed between unaffected parents and controls (p < 0.01). Notably, these changes were specific to parents with a positive family history of CL/P. Shape changes associated with CL/P predisposition included marked flattening of the facial profile (midface retrusion), reduced upper facial height, increased lower facial height, and excess interorbital width. Additionally, a sex-specific pattern of parent-control difference was evident in the transverse dimensions of the nasolabial complex.


CONCLUSIONS
The faces of unaffected parents from multiplex cleft families displayed meaningful shape differences compared with the general population. Quantitative assessment of the facial phenotype in cleft families may enhance efforts to discover the root causes of CL/P.
Center for Craniofacial and Dental Genetics, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA, USA. smwst46@pitt.edu
S M
SM
Weinberg
S D
SD
Naidoo
K M
KM
Bardi
C A
CA
Brandon
K
K
Neiswanger
J M
JM
Resick
R A
RA
Martin
M L
ML
Marazita
D016022:Case-Control Studies; D002508:Cephalometry; D002971:Cleft Lip / Q000235:genetics*; D002972:Cleft Palate / Q000235:genetics*; D005145:Face / Q000033:anatomy & histology*; D005192:Family Health; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D021621:Imaging, Three-Dimensional; D008046:Lip / Q000033:anatomy & histology; D008297:Male; D008445:Maxillofacial Development / Q000235:genetics; D009666:Nose / Q000033:anatomy & histology; D009915:Orbit / Q000033:anatomy & histology; D010290:Parents; D010780:Photogrammetry; D025341:Principal Component Analysis; D012737:Sex Factors; D014716:Vertical Dimension; D015050:Zygoma / Q000033:anatomy & histology