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Background Otocephaly or dysgnathia complex is characterised by mandibular hypoplasia/agenesis, ear anomalies, microstomia, and microglossia; the molecular basis of this developmental defect is largely unknown in humans. Methods and results This study reports a large family in which two cousins with micro/anophthalmia each gave birth to at least one child with otocephaly, suggesting a genetic relationship between anophthalmia and otocephaly. OTX2 , a known microphthalmia locus, was screened in this family and a frameshifting mutation was found. The study subsequently identified in one unrelated otocephalic patient a sporadic OTX2 mutation. Because OTX2 mutations may not be sufficient to cause otocephaly, the study assayed the potential of otx2 to modify craniofacial phenotypes in the context of known otocephaly gene suppression in vivo. It was found that otx2 can interact genetically with pgap1 , prrx1 , and msx1 to exacerbate mandibular and midline defects during zebrafish development. However, sequencing of these loci in the OTX2-positive families did not unearth likely pathogenic lesions, suggesting further genetic heterogeneity and complexity. Conclusion Identification of OTX2 involvement in otocephaly/dysgnathia in humans, even if loss of function mutations at this locus does not sufficiently explain the complex anatomical defects of these patients, suggests the requirement for a second genetic hit. Consistent with this notion, trans suppression of otx2 and other developmentally related genes recapitulate aspects of the otocephaly phenotype in zebrafish. This study highlights the combined utility of genetics and functional approaches to dissect both the regulatory pathways that govern craniofacial development and the genetics of this disease group.

We present the in utero appearances and postmortem radiographic findings of two sib fetuses, a male and a female, with features suggestive of kyphomelic dysplasia. The fetuses had severe bowing of the long bones, short, flared ribs, platyspondyly, metaphyseal flaring, skin dimpling, with normal external genitalia and karyotypes and a normal pregnancy. They were born to a mother with features of brachydactyly type E. Prenatal ultrasonography of each case showed a normal amount of amniotic fluid, a normal brain, a normal biparietal diameter, symmetrical bowing and shortening of the long bones, and a narrow thorax. Our cases provide support for a familial mode of inheritance for both sexes in kyphomelic dysplasia. Prenatal ultrasound examination can be offered in subsequent pregnancies.

We report on the prenatal diagnosis of a case of cebocephaly, alobar holoprosencephaly, and microcephaly associated with a de novo proximal interstitial deletion of the long arm of chromosome 14: del(14)(q13q21.1) or (q13q21.2). This is the third case of holoprosencephaly in association with a deletion in this region. The present report concerns the association between prenatal craniofacial development, a holoprosencephaly locus, and the chromosomal segment 14q13.