title: Orbicularis oris muscle defects as an expanded phenotypic feature in nonsyndromic cleft lip with or without cleft palate.
abstract: 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.
authors.affiliation: 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.
authors.forename: Katherine
authors.initials: K
authors.lastname: Neiswanger
authors.forename: Seth M
authors.initials: SM
authors.lastname: Weinberg
authors.forename: Carolyn R
authors.initials: CR
authors.lastname: Rogers
authors.forename: Carla A
authors.initials: CA
authors.lastname: Brandon
authors.forename: Margaret E
authors.initials: ME
authors.lastname: Cooper
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Bardi
authors.forename: Frederic W B
authors.initials: FW
authors.lastname: Deleyiannis
authors.forename: Judith M
authors.initials: JM
authors.lastname: Resick
authors.forename: A'Delbert
authors.initials: A
authors.lastname: Bowen
authors.forename: Mark P
authors.initials: MP
authors.lastname: Mooney
authors.forename: Javier Enríquez
authors.initials: JE
authors.lastname: de Salamanca
authors.forename: Beatriz
authors.initials: B
authors.lastname: González
authors.forename: Brion S
authors.initials: BS
authors.lastname: Maher
authors.forename: Rick A
authors.initials: RA
authors.lastname: Martin
authors.forename: Mary L
authors.initials: ML
authors.lastname: Marazita
mesh_terms: 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