Orbicularis oris muscle defects as an expanded phenotypic feature in nonsyndromic cleft lip with or without cleft palate.
Nonsyndromic cleft lip+/-cleft palate is a complex disease with a wide phenotypic spectrum; occult defects of the superior orbicularis oris muscle may represent the mildest subclinical form of the lip portion of the phenotype. This study used high-resolution ultrasonography to compare the frequency of discontinuities in the OO muscle in 525 unaffected relatives of individuals with nonsyndromic cleft lip+/-cleft palate versus 257 unaffected controls. OO muscle discontinuities were observed in 54 (10.3%) of the non-cleft relatives, compared to 15 (5.8%) of the controls-a statistically significant increase (P=0.04). Male relatives had a significantly higher rate of discontinuities than male controls (12.0% vs. 3.2%; P=0.01); female relatives also had a higher rate of discontinuities than female controls, but the increase was not statistically significant (8.9% vs. 7.4%; P=0.56). These data confirm the hypothesis that subepithelial OO muscle defects are a mild manifestation of the cleft lip phenotype. Identification of subepithelial OO muscle defects may be important in a clinical setting, as a means of providing more accurate recurrence risk estimates to relatives in cleft families. Furthermore, the expansion of the cleft lip+/-cleft palate phenotypic spectrum should improve the power of genetic studies.
Neiswanger
Katherine
K
Center for Craniofacial and Dental Genetics, Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, and Department of Pediatric Radiology, Children's Hospital of Pittsburgh, Pennsylvania 15219, USA.
Weinberg
Seth M
SM
Rogers
Carolyn R
CR
Brandon
Carla A
CA
Cooper
Margaret E
ME
Bardi
Kathleen M
KM
Deleyiannis
Frederic W B
FW
Resick
Judith M
JM
Bowen
A'Delbert
A
Mooney
Mark P
MP
de Salamanca
Javier Enríquez
JE
González
Beatriz
B
Maher
Brion S
BS
Martin
Rick A
RA
Marazita
Mary L
ML
D002971:Cleft Lip / Q000150:complications*; D002972:Cleft Palate / Q000150:complications*; D005152:Facial Muscles / Q000002:abnormalities* / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D010641:Phenotype; D012727:Sex Characteristics; D014463:Ultrasonography