Causes of Deafblindness
More than 70 causes (also known as etiologies) of deafblindness were identified in the 2019 National Deaf-Blind Child Count. The most common are complications of prematurity and CHARGE syndrome, with each causing approximately 10% of cases.
This page provides brief descriptions and links to resources for some of the more common—although still relatively rare—syndromes and prenatal/congenital causes. Unless otherwise noted, the descriptions are from the National Institutes of Health.
CHARGE syndrome is a disorder that affects many areas of the body. CHARGE is an abbreviation for several of the features common in the disorder: coloboma, heart defects, atresia choanae (also known as choanal atresia), growth retardation, genital abnormalities, and ear abnormalities.
Usher syndrome is a condition characterized by partial or total hearing loss and vision loss that worsens over time. The hearing loss is classified as sensorineural, which means that it is caused by abnormalities of the inner ear. The loss of vision is caused by an eye disease called retinitis pigmentosa, which affects the layer of light-sensitive tissue at the back of the eye (the retina). Three major types, I, II, and III, have been identified.
Down Syndrome (Trisomy 21)
Down syndrome is a chromosomal condition associated with intellectual disability, a characteristic facial appearance, and weak muscle tone in infancy. All affected individuals experience cognitive delays, but the intellectual disability is usually mild to moderate. Individuals with Down syndrome have an increased risk of hearing and vision problems and a variety of birth defects.
Stickler syndrome is a group of hereditary conditions characterized by a distinctive facial appearance, eye abnormalities, hearing loss, and joint problems. These signs and symptoms vary widely among individuals. The hearing loss may be sensorineural, meaning that it results from changes in the inner ear, or conductive, meaning that it is caused by abnormalities of the middle ear. Eye conditions include severe nearsightedness, glaucoma, cataracts, and retinal detachment.
Dandy-Walker is a brain developmental condition in which the cerebellum, the part of the brain responsible for the coordination of movement, is malformed. Hydrocephaly is a related complication due to cysts that form in the brain's fourth ventricle and block the flow of cerebrospinal fluid (CSF). This blockage allows excessive CSF to accumulate, swelling the ventricle and putting pressure on the brain. (Fields, n.d.)
Goldenhar syndrome is present at birth and mainly affects the development of the eye, ear, and spine. The primary characteristics are facial asymmetry, a partially formed or totally absent ear, noncancerous growths of the eye, and spinal abnormalities. It may also affect the heart, lungs, kidneys, and central nervous system and is due to problems that occur when the fetus is forming within the womb of the mother. The cause is unknown.
Zellweger Spectrum Disorder
Zellweger spectrum disorder, also referred to as peroxisome biogenesis disorders, is a group of conditions that affect many parts of the body. Characteristics include weak muscle tone, hearing and vision loss, seizures, liver dysfunction, and developmental delay. This group of conditions includes Zellweger syndrome, neonatal adrenoleukodystrophy (NALD), and infantile Refsum disease. These conditions were once thought to be distinct disorders but are now considered to be part of the same spectrum. Zellweger syndrome is the most severe form, NALD is intermediate in severity, and infantile Refsum disease is the least severe. Some researchers prefer not to use the separate condition names but instead refer to cases as severe, intermediate, or mild.
Cornelia de Lange Syndrome
Cornelia de Lange syndrome is a developmental disorder that affects many parts of the body. Features vary widely among individuals, ranging from relatively mild to severe. Potential characteristics include slow growth, intellectual disability, distinctive facial features, behavior similar to autism, an unusually small head, hearing loss, and eye problems.
Cytomegalovirus (CMV), is a common virus that infects people of all ages. Most people infected with CMV show no signs or symptoms. When a baby is born with cytomegalovirus infection, it is called congenital CMV and may cause brain, liver, spleen, lung, and growth problems. The most common long-term issue is hearing loss, which may be present at birth or develop later in childhood (CDC, 2019). It can also cause visual impairments, including strabismus, cortical visual impairment, nystagmus, and optic nerve atrophy (Jin et al., 2017).
Hydrocephalus is a condition in which the primary characteristic is excessive accumulation of cerebrospinal fluid (CSF) that can lead to potentially harmful pressure on the tissues of the brain. Symptoms vary by age. In infancy, they include a rapid increase in head circumference, vomiting, downward deviation of the eyes, and seizures.
High CSF pressure can damage vision due to pressure on the optic nerve or other nerves (Roumila, n.d.). It may also cause hearing loss , believed to be due directly to hydrocephalus or as a side effect of surgical shunt placement (in some cases, however, shunting has been found to resolve hearing loss) (Satzer & Guillaume, 2016).
Microcephaly is a condition in which a baby’s head is much smaller than expected. It can be an isolated condition or can occur in combination with other major birth defects. Signs and symptoms associated with microcephaly in infants depend on the severity of the condition and include seizures, developmental delay, intellectual disability, problems with movement and balance, feeding problems, and vision and hearing loss. (CDC, 2020).
Centers for Disease Control and Prevention. (2019). Cytomegalovirus (CMV) and congenital CMV infection.
Centers for Disease Control and Prevention. (2020). Facts about microcephaly.
Fields, C. J. (n.d.). Dandy-Walker syndrome. University of Nevada, Reno, Nevada Dual Sensory Impariment Project.
Roumila, K. (n.d.). Papilledema, vision loss, and hydrocephalus. Hydrocephalus Association.
Jin, H. et al. (2017). Long-term visual and ocular sequelae in patients with congenital cytomegalovirus infection. Pediatric Infectious Disease Journal, 36(9), 877-882.
Satzer, D., & Guillaume, D. J. (2016). Hearing loss in hydrocephalus: A review, with focus on mechanisms. Neruosurgical Review, 39, 13-25.