Congenital malformations - Edocr

108 PART III CRANIOFACIAL MALFORMATIONS
sensorineural types. The disorder varies from
mild to severe, and involvement is usually unilateral
(70%) with right sided preponderance.
ETIOLOGY AND INCIDENCE
The incidence of OAV spectrum is approximately
1/3000–1/5600 live births with a male preponderance
of 3:2. 13 Embryologically, the OAV
defects have been described as defects of development
of the first and second branchial arches.
The first pair of arches are involved in the formation
of facial bones (maxilla, zygoma,
mandible, and ear ossicles), related muscles and
ligaments, and cranial nerves V and VII. However,
this mechanism does not explain the
anomalies of the brain, heart, kidneys, or spine
that are commonly associated with the craniofacial
anomalies (see below). It has been suggested
that the OAV spectrum is a disorder of
blastogenesis and the developing midline, occurring
during the first 4 weeks of embryonic
development. 14
OAV appears to be an etiologically heterogenous
disorder. Teratogenic effects have
been identified as this condition has been noted
in infants of diabetic mothers, in fetal alcohol
syndrome, and in infants exposed to retinoic
acid. In addition, multiple chromosome abnormalities
have been identified in infants with features
of the OAV spectrum.
ASSOCIATED MALFORMATIONS
In addition to craniofacial and vertebral abnormalities,
visceral anomalies including cardiac
(5–30%) and renal defects may occur in the OAV
spectrum. The most common cardiac defects are
ventricular septal defect and patent ductus arteriosus.
Renal anomalies include renal agenesis,
ectopic or fused kidneys, vesicoureteral reflux,
ureteropelvic junction obstruction, and multicystic
dysplastic kidneys. A wide range of central
nervous system (CNS) defects occur occasionally,
including hydrocephalus, Chiari malformation,
and agenesis of the corpus callosum.
TABLE 15-1 Recommended Diagnostic
Studies for Evaluation of Oculo-Auriculo-
Vertebral Spectrum
Echocardiogram
Renal ultrasound
Vertebral x-rays
CNS imaging (if abnormal neurological
findings)
Hearing evaluation
Ophthalmology evaluation
Chromosome analysis
EVALUATION
A detailed prenatal history should be obtained
to identify any maternal drug exposures or diabetes
mellitus. Because of the complexity of this
spectrum, infants with craniofacial features of OAV
spectrum should undergo a systematic search for
associated skeletal or visceral malformations, as
well as hearing and ophthalmologic evaluations
(Table 15-1). In addition, chromosome analysis is
warranted to exclude the possibility of a chromosome
abnormality as a cause of the congenital
anomalies.
PROGNOSIS
Plastic surgery may be warranted in cases with severe
facial deformities or ear anomalies. Hearing
evaluations in early infancy are important to identify
any significant hearing loss. Most individuals
have normal intelligence in the absence of major
CNS anomalies or a chromosome abnormality.
GENETIC COUNSELING
Most cases of OAV spectrum are sporadic, but
familial instances with apparent autosomal dominant
inheritance with variable expressivity have
been reported. As the disorder is most likely genetically
and etiologically heterogeneous, the
empiric recurrence risk is about 2–3%.