What is Oculo-Auriculo-Vertebral Spectrum?

Oculo-auriculo-vertebral spectrum or OAVS is a developmental disorder of craniofacial morphogenesis.

A complex congenital condition, OAVS is associated with anomalies of the ear, head, neck, and vertebra. Clinical manifestations of OAVS can range from mild or moderate facial asymmetry to severe form with obvious facial deformities. The first and second pharyngeal arches' defective development is the root of the problem.

Although the origin of OAVS is not yet identified, it is likely complex. Due to the wide range of anomalies and variations in the severity of presentation, managing patients with OAVS is difficult.

History of oculo-auriculo-vertebral spectrum

In 1952, Maurice Goldenhar, an ophthalmologist, initially identified OVAS as a correlation between ophthalmic, auricular, and facial traits. Vertebral abnormalities were then included on the list by Gorlin et al. in 1963.

Oculoauriculovertebral dysplasia was proposed by Gorlin et al. (1963). Goldenhar syndrome, facio-auriculo-vertebral syndrome, or Goldenhar-Gorlin syndrome are other names for the condition.

OAVS represents a phenotypic continuum with a sizable overlap between abnormalities of first and second branchial arches-derived structures. This includes the mandible, maxilla, ears, lips, tongue, and palate.

Causes and symptoms of oculo-auriculo-vertebral spectrum

Although the exact cause of OAVS is still unknown, it is believed to be complex and likely to involve both environmental and genetic factors. A number of genes have been found to be associated with this condition.

The environmental factors include maternal or prenatal factors like gestational diabetes mellitus, twin or multiple pregnancies, maternal hypothyroidism, celiac disease, thalidomide, disruption of embryonic blood flow, use of vasoactive drugs, and hormonal therapy, exposure to tamoxifen, smoking, and older age group of parents.

Numerous intrauterine medication exposures have been connected to the OAVS. For example, it was discovered that vasoactive drug use by pregnant women combined with cigarette smoking during the first trimester was linked to a higher incidence of OAVS.

This widely recognized theory postulates that the elements mentioned above will alter embryonic blood flow as it develops. Premature birth and vaginal hemorrhage during pregnancy are examples of intranatal variables.

A newborn exposed to cocaine also showed severe OAVS symptoms. A small number of authors have also suggested epigenetic processes to explain how genetic and environmental variables interact.

A set of abnormalities collectively known as OAVS predominantly affect the first and second branchial arches, as well as the first pharyngeal pouch and branchial cleft that they are connected through.

Specifically, the ear, mouth, mandible, eye, and cervical spine are included in this. The involvement of several systems is highly typical of OAVS. Symptoms and examination results can be categorized based on the organ system involved.

The mandibular hypoplasia with facial asymmetry, oculo-auricular malformations, and spinal abnormalities make up the typical triad of OAVS.

Epibulbar and lipodermoids, as well as auricular abnormalities such as microtia, hemifacial microsomia, preauricular tags, appendages, and fistula, are among the most prevalent clinical characteristics.

Vertebral abnormalities and hypoplasia of numerous bones, such as the maxilla, mandible, zygomatic arch, and malar region, are additional common features. There have also been reports of mental impairment and global developmental delay.

The most prevalent systemic malformations are ear abnormalities (100%) followed by eye involvement (72%), spinal malformations (67%), and congenital heart defects (33%).

There have also been reports of other functional deficiencies in OAVS, including autistic spectrum disorder, speech problems, dysphagia, hearing loss, and low eyesight. There are reports of scoliosis and spinal cord anomalies in the cervical spine as well.

Genetics and inheritance in oculo-auriculo-vertebral spectrum

By using traditional karyotyping or array comparative genomic hybridization on OAVS patients, many chromosomal aberrations have been found. Numerous times, the link with chromosomes 5, 9, 18, 22, and X was noted. In 2–12% of cases, family history has been mentioned.

Both familial and sporadic variants of OAVS share comparable phenotypic traits. The risk of OAVS in first-degree relatives of an affected person is between 2 and 3%. Segregation analysis has revealed that genetic transmission may occur in some familial cases of OAVS, which typically occur sporadically.

Furthermore, according to clinical investigations, up to 45% of "unaffected" relatives of probands with OAVS do have modest OAVS signs after rigorous history-taking and clinical assessment. Both autosomal dominant and autosomal recessive inheritance are observed in familial situations. It has been noted that inheritance patterns are complicated.

Epidemiology of oculo-auriculo-vertebral spectrum

The prevalence of OAVS ranges from 1 per 3500 to 1 in every 45,000 live births. OAVS affects male infants more frequently than female neonates (3 to 2). The affected children typically live regular lives and with normal intelligence.

Diagnosis and treatment of oculo-auriculo-vertebral spectrum

There are no universally accepted diagnostic standards for OAVS. Asymmetric hypoplasia of the facial structures with preauricular tags and/or microtia is one of the suggested minimal diagnostic criteria for OAVS.

The OMENS classification (consisting of an Orbit, Mandible, Ear, Nerve, and Soft tissue grading system), established by Vento et al. in 1991, is one attempt to categorize common anomalies linked with OAVS. Later, in 1995, Horgan et al. expanded it to accommodate extracranial features, giving it the name "OMENS plus."

Starting in the first few days of life, the management of patients with OAVS necessitates an interdisciplinary approach. Pediatricians and neonatologists make the diagnosis of congenital abnormalities and begin treatment immediately after birth. After a thorough examination, management should be personalized for the patient and concentrate on raising the quality of life.

It is challenging to develop evidence-based guidelines for the diagnosis and management of this complicated condition because of the etiology, high phenotypic heterogeneity, and variations in management. This implies that a patient's treatment will vary depending on their symptoms and be specific to them. To clarify the diagnosis and create a care plan, more genetics research is required.

References

• Singhal D, & Tripathy K. Oculo Auriculo Vertebral Spectrum. [Updated 2022 Feb 21]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK576398/
• Tingaud-Sequeira A, Trimouille A, Sagardoy T, et al. (2022). Oculo-auriculo-vertebral spectrum: new genes and literature review on a complex disease. Journal of Medical Genetics, 59(5), 417–427. doi:10.1136/jmedgenet-2021-108219
• Glaeser AB, Santos AS, Diniz BL, et al. (2020). Candidate genes of oculo-auriculo-vertebral spectrum in 22q region: A systematic review. American Journal of Medical Genetics. Part A, 182(11), 2624–2631. doi:10.1002/ajmg.a.61841
• Vong A, & Funamura J (2018). Multidisciplinary management of oculo-auriculo-vertebral spectrum. Current Opinion in Otolaryngology & Head and Neck Surgery, 26(4), 234–241.  doi:10.1097/MOO.0000000000000468
• Beleza-Meireles A, Hart R, Clayton-Smith J, et al. (2015). Oculo-auriculo-vertebral spectrum: clinical and molecular analysis of 51 patients. European Journal of Medical Genetics, 58(9), 455–465.  doi:10.1016/j.ejmg.2015.07.003
• Manara R, Brotto D, Ghiselli S, et al. (2015). Cranial Nerve Abnormalities in Oculo-Auriculo-Vertebral Spectrum. AJNR. American Journal of Neuroradiology, 36(7), 1375–1380.  doi:10.3174/ajnr.A4273
• Beleza-Meireles A, Clayton-Smith J, Saraiva JM, et al. (2014). Oculo-auriculo-vertebral spectrum: a review of the literature and genetic update. Journal of Medical Genetics, 51(10), 635–645.  doi:10.1136/jmedgenet-2014-102476
• Barisic I, Odak L, Loane M, et al. (2014). Prevalence, prenatal diagnosis and clinical features of oculo-auriculo-vertebral spectrum: a registry-based study in Europe. European Journal of Human Genetics: EJHG, 22(8), 1026–1033.  doi:10.1038/ejhg.2013.287

Further Reading

• All Craniofacial Content
• Craniofacial and Dental Genetics