Accidents - Klippel-Feil
Accidents, see Trauma
Also called chondro-dystrophy. An inherited condition (autosomal dominant), but can also arise as a new mutation; incidence is roughly 1 per 25,000 births, and affects both sexes. Characterized by short stature (dwarfism). Frequent middle ear infections are common, which can lead to conductive deafness later in life due to the repeated ear infections. Sensorineural deafness can also occur. DSID p.9-13, EGDBD p.5-6.
Acoustic neuroma, see Auditory nerve tumors
Sensorineural hearing loss caused by exposure to excessive noise or abnormally loud sound. It may be cumulative (building up from repeated exposure, as from daily working in noisy environments) or abrupt, as from a single exposure to an extremely loud sound such as an explosion. The eardrum may be ruptured, and the middle ear bones can be disrupted. Often, significant damage to the hair cells inside the cochlea results in permanent hearing loss, as hair cells, like most other nerve tissue, do not regenerate themselves. GEDPD v.2 p.17-20, 151-152; EDHD2 p.4; EDHD p.2.
Adair-Dighton syndrome, see Van der Hoeve syndrome
Normally shrinking after about age 5 and disappearing by adolescence, on occasion the adenoids (lymph glands at the back of the nose) continue to grow instead and may obstruct the Eustachian tube, causing conductive hearing impairment and nasal infections that can spread to the middle ear. This condition is corrected by surgical removal of the adenoids. EDHD2 p.5; EDHD p.3.
Adhesive otitis media, see Otitis media
Adult myxedema, see Thyroid disorders
Aero-otitis media, see Barotrauma
Aging, see Presbycusis
AIDS (Acquired Immunodeficiency Syndrome)
Infection by the human immunodeficiency virus (HIV) can result in AIDS or in AIDS-related complex (ARC). Both are associated with neurological complications that often include hearing loss. "Auditory system anomalies" afflict an estimated 75% of adult AIDS patients and 50% of all ARC patients. Hearing disorders may be caused directly by HIV infection of the cochlea or of the central auditory system, but are often caused by opportunistic infections rather than HIV itself-i.e., the body's loss of its normal resistance to infection allows other non-related infections to take hold. The most common of these opportunistic infections is cytomegalovirus inclusion disease (CMV) (q.v.), which is found in over 90% of AIDS patients. EDHD2 p.7.
AIDS-related complex (ARC), see AIDS
These crash safety devices, installed in nearly all passenger cars today, can be as loud as 150-170 dB for about 0.1 seconds when triggered, possibly causing tinnitus or acoustic trauma (q.v.). EDHD2 p.7.
Alcohol, see Fetal alcohol syndrome
Partial deafness; minor vision problems with normal visual fields, dark vision and color vision.
Alport syndrome or Alport disease
Also called hereditary nephritis, familial nephritis, or Fetchner syndrome. Genetic (genes COL4A5, COL4A3, and COL4A4). It may be inherited in two ways: in an X-linked manner, in which twice as many females as males are affected, but the males tend to be more severely affected; or as an autosomal dominant characteristic, in which case equal numbers of both sexes are affected (this latter variety is also called Fetchner syndrome). Can be passed on to successive generations. Characteristics, generally appearing in mid-childhood, include nephritis (blood and/or protein in the urine) in all cases and progressive degeneration of kidney function leading to renal failure. Kidney dialysis and/or kidney transplants are eventually required. About half of all Alport syndrome cases, males more commonly than females, have progressive sensorineural deafness from the toxic effects of unremoved body metabolic waste products on membranes in the cochlea. This deafness may appear as early as age 3 or 4. DSID p.25-28; EDHD2 p.9; EDHD p.7; GEDPD v.2 p.31; EGDBD p.128.
Andre syndrome, see Oto-palato-digital syndrome
Anoxia, see Asphyxia at birth
A rare condition characterized by premature fusion of the bones of the skull along the sutures (edges of the bone plates). Though it can be inherited (autosomal dominant), most cases seem to arise as new mutations. Among other facial, cranial and manual malformations, the ears tend to be low-set and a congenital hearing loss is frequently present. DSID p.35-37; EGDBD p.30.
Asphyxia at birth
Difficulties during delivery of the infant at birth can cause the infant to go without oxygen for a dangerously long period of time (anoxia--total loss of oxygen, or more usually hypoxia--reduced oxygen supply). The permanent neurological damage that can result includes sensorineural hearing impairment in about 3% of cases. GEDPD v.2 p.25; EDHD2 p.15-16.
Aspirin, see Ototoxic drugs
Atresia of the ear is a birth defect in which the opening of the external ear is nearly closed or entirely absent, blocking sound from entering the middle ear. Post-birth, it can also result from burns, tumors, accidents, and infections. It can be corrected by surgically making the necessary opening. EDHD2 p.20, EGDBD p.33.
Auditory nerve tumors
Tumors may grow on the auditory nerve, causing hearing impairment on the affected side. Most common in women between 40 and 60 years of age. If it occurs on both sides, this is usually an inherited form indicating central neurofibromatosis (q.v.). EDHD2 p.26-27; EDHD p.26-27.
An inflammation of the auditory nerve following infections such as scarlet fever, typhoid fever, or other infections having high fevers. Deafness may be immediate but is usually progressive over several days or weeks. EDHD2 p.27.
Autoimmune inner ear disease (AIED)
Several autoimmune diseases can cause or are associated with AIED, in which immune cells attack the inner ear, causing deafness and/or dizziness. Relatively rapid hearing loss plus tinnitus over a period of a few months, or attacks of hearing loss and tinnitus resembling Ménière disease. Half of all victims also have balance problems. Rare, accounting for less than 1% of all cases of hearing impairments or dizziness. EDHD2 p.29.
Bacterial labyrinthitis, see Labyrinthitis
Bacterial meningitis, see Meningitis
Also called Laurence-Moon-Bardet-Biedl syndrome. A familial syndrome comprising retinitis pigmentosa, polydactyly, intellectual retardation, obesity of the Frohlich type and genital hypoplasia. Sometimes accompanied by deafness. Autosomal recessive inheritance. EGDBD p.39.
Barotitis, see Barotrauma
Also known as aero-otitis media or barotitis. A temporary but painful condition where external air pressure and pressure in the middle ear are significantly different, causing great pressure on the eardrum. It can be experienced by rapid descent in a poorly-pressurized airplane, diving in water to more than a few feet deep, or other quick changes of surrounding pressure. In extreme cases, the eardrum may rupture, causing some reduced hearing even after it heals, due to scarring. EDHD2 p.5; EDHD p.3.
Bilateral acoustic neurofibromatosis, see Neurofibromatosis
Deafness often results from one or more birth defects. There are hundreds of different birth defects associated with deafness, mostly from genetic causes but many from factors affecting the development of the fetus during pregnancy, such as ototoxic drugs and substances, trauma to the mother also affecting the fetus, syphilis, and many others. Most of these are included throughout this document.
Genetic (gene EYA1 and one other unidentified).
Brailsford syndrome, see Morquio syndrome
Brittle bone disease, see Osteogenesis imperfecta
Cancer of the outer ear
Usually appears in areas of the external ear exposed to the sun for years, and therefore is a variety of skin cancer. If caught and treated early, recovery rate is very high. The main risk is from cancer that may begin inside the ear canal, spreading to the surrounding bone before being discovered and far more serious to treat. Survival of such cancer nearly always includes deafness in the affected ear. EDHD2 p.42.
Cardio-cutaneous syndrome, see LEOPARD syndrome
Caused by inflammation of the mucous membrane lining the head's and throat's air passages, combined with a blocked Eustachian tube. Results from an ear infection; antibiotics and decongestants are the usual treatment. EDHD2 p.43.
Any of several non-progressive disorders of movement, posture or speech caused by brain damage during pregnancy, birth or early childhood. 0.2% to 0.6% of infants develop cerebral palsy before or during birth; postnatal causes can be from head injury, encephalitis (q.v.) or meningitis (q.v.). Hearing impairment occurs in about 25% to 30% of cerebral palsy victims. EDHD2 p.44; EGDBD p.57-58.
Cerebro-spinal meningitis, see Meningitis
An excess buildup of cerumen (earwax) in the ear canal can cause temporary conductive deafness either by stopping up the ear canal or by pressing against the eardrum and restricting its vibration. The solution is simply removal of the excess earwax, either by a doctor or under a doctor's direction. EDHD2 p.72.
Cervical fusion syndrome, see Klippel-Feil syndrome
Charcot-Marie-Tooth disease (CMT)
Also known as peroneal muscular atrophy. A familial disease characterized by muscle weakness, mainly in the lower limbs, from degeneration of the nerves supplying the muscles. Usually inherited as autosomal dominant, but can also be inherited as autosomal recessive. Research suggests that a duplication of part of chromosome 17 seems to be responsible for CMT. Severity of symptoms vary in individual cases, but include the following symptoms that do not arise until age 10 or later: awkward gait with progressive wasting of the lower leg muscles and foot drop, a similar but usually milder effect on the upper limbs, nephritis in a few cases, and in many cases a sensorineural hearing loss manifesting itself as early as the teenage years, often becoming severe by early middle age. DSID p.56-58; EGDBD p.59-60.
Also known as CHARGE syndrome or choanal atresia. The acronym CHARGE comes from the list of the main features seen in this rare condition, which was first identified only in 1979. Cause is not yet clear, but both autosomal dominant and recessive modes of inheritance have been identified. Symptoms include Colomba of the eye, Heart disease, coanal Atresia, Retarded growth, Genital hypoplasia, and Ear abnormalities. The latter are not always present, but ears may be very small or have a characteristic triangular shape; deafness may also occur, ranging from mild to profound and can be either conductive or sensorineural. DSID p.59-62; EGDBD p.60.
Chicken pox, see Varicella zoster
This venereal disease affecting women has been documented as causing hearing loss in newborns to whom the disease has been passed at birth.
Choanal atresia, see CHARGE association
A rare and serious chronic condition in which skin cells and debris collect within the middle ear, usually as a result of a middle ear infection that has caused the eardrum to burst. May be present at birth or later in life; there is also a very rare congenital variety. Left untreated, the cholesteatoma may grow and damage the middle ear bones and surrounding bony structure, causing a conductive or mixed conductive-sensorineural hearing loss. Serious additional complications can include secondary infections, labyrinthitis (q.v.), meningitis (q.v.) or a brain abscess. EDHD2 p.47.
Chondro-dystrophy, see Achondrophasia
A middle ear tumor usually accompanying a middle ear malformation. Although itself benign, this tumor can cause conductive deafness by physically filling the middle ear, destroying the ossicles and restricting eardrum movement. EDHD2 p.48.
Chromosome 45/X syndrome, see Turner syndrome
Some children with cleft palate also have mild to moderate hearing impairments due to the cleft condition also deforming the middle ear. This is usually treatable through surgery. EDHD2 p.48; EGDBD p.72-73.
Cockayne syndrome or Cockayne disease
A very rare genetic syndrome (inherited as autosomal recessive); its effects are thought to be from an enzyme defect. Onset of symptoms as early as the second year of life, usually after a normal infancy. Great photosensitivity of the skin, with pigmentation and scars; progressive decrease of vision, mental deficiency, unsteady gait, progressive sensorineural deafness, dwarfism, and precociously senile appearance. Death usually in early childhood, but some survive into the late teens. DSID p.66-67; EGDBD p.75.
Also known as Coffin syndrome. An X-linked recessive hereditary disease, with some additional cases believed to arise frequently through new mutations. Mental retardation, short stature from spinal defects, and puffy-appearing fingers are usual; deafness sometimes occurs also. Males tend to be afflicted to a greater extent than females. DSID p.68-69; EGDBD p.75-76.
Affects mostly young adults, occasionally old persons. Sudden onset of unilateral or bilateral blurring of vision, inflammation of the cornea and pain in the eye, lacrimation, blepharospasm, nausea, vomiting, tinnitus, vertigo, and rapid development of deafness. About 50% of patients have an associated systemic disease, most commonly polyarteritis nodosa. EDHD2 p.55; EDHD p.49; GEDPD v.2 p.31.
Congenital brevicollis, see Klippel-Feil syndrome
Congenital central hypoventilation syndrome
Also sometimes called Ondine's curse. A rare condition that may be congenital or may follow an acquired viral encephalitis (q.v.), affecting both sexes. Cause has not been definitively established, but is almost certainly a genetic fault. Characterized by breathing difficulties and apnea, especially during sleep; cyanosis (blue skin) soon after birth is often the first noticeable symptom. Problems with body temperature control, seizures, and urine production; hearing problems have also been reported in some cases. DSID p.73-75; EGDBD p.246.
Congenital cytomegalic inclusion disease (CID)
A systemic disease due to infection of the fetus by cytomegalovirus. Significant damage to the central nervous system occurs in about 10% of affected infants. Intellectual retardation; in 50% of cases, microcephaly and occasionally hydrocephalus. Accompanying sensorineural deafness. Postnatal CID infection is usually benign.
Craniofacial dystosis, see Crouzon syndrome
Also known as craniofacial dystosis. A rare condition; half of the cases are inherited (autosomal dominant) and the other half appears as a fresh mutation. Characterized by a premature fusion of the cranial sutures (the edge of the bony plates making up the skull); small head, sometimes cleft palate, a beaked nose, and protruding eyes. Learning disabilities are common, and underdevelopment of the external meatus (pinna) of the ear can cause hearing impairment. DSID p.82-84; EGDBD p.89-90.
Cytomegalovirus inclusion disease (CMV)
Affects developing fetuses if the mother becomes infected with CMV during pregnancy; roughly 11% of infected infants have some degree of hearing loss, usually profound but sometimes milder. Different reports blame CMV for between 2 and 40 percent of all congenital deafness, rivaling rubella as the most common viral cause of prenatal deafness. It is also found in over 90% of AIDS patients as an opportunistic infection. EDHD2 p.7, 60; GEDPD v.2 p.23.
D1 Trisomy syndrome, see Trisomy 13 syndrome
Diabetes mellitus type II and sensorineural hearing loss
A genetic (mitochondrial) condition caused by mutations. Diabetes can cause blood vessels and peripheral nerves to degenerate, disrupting blood supply to, among other places, the ear and the internal auditory canal. This in turn can cause a degeneration of cochlear and vestibular nerves, causing a sensorineural hearing loss. EDHD2 p.65; EGDBD p.99-101.
Distopia canthorum, see Waardenburg syndrome
Diuretics, see Ototoxic drugs and other substances
Also known as mongolism (obsolete) or trisomy 21. Caused by a chromosomal abnormality which can express itself in two different ways: Most commonly, an extra chromosome is added in the 21 position, leading to a chromosome count of 47 instead of the normal 46. Much less often, the extra chromosome attaches to another chromosome, leading to a normal count of 46, but one of these is a "compound" chromosome. Overall incidence in Caucasian, Japanese, and African American populations ranges between 1 in 660 births and 1 in 800 births, and is also sensitive to the age of the mother, with risk rising sharply when she is over 35. Both sexes can be affected. Very characteristic facial features including an upward slant to the eyes; the head may be smaller and flatter at the back and with a short neck. Eye abnormalities may be present, limbs are relatively short, fingers are short and stubby, and muscle tone is poor. Delay and slowness in mental development (not mental deficiency). Conductive deafness often occurs from frequent middle ear infections, and in some cases Down patients are born with irregularities in the middle and inner ears that can also cause conductive hearing impairment. DSID p.90-94; EDHD2 p.66; EGDBD p.104-106.
Drugs, see Ototoxic drugs and other substances
Dwarfism (very short stature) is not in itself a cause of deafness. However, many of the causes of dwarfism also cause deafness. Achondroplasia (q.v.) accounts for approximately half of all cases of dwarfism and commonly also involves deafness. Other causes of dwarfism with deafness may include chromosome abnormalities such as Turner syndrome (q.v.), spondyloepiphyseal dysplasia (q.v.) and some ototoxic drugs and other substances (q.v.) and other teratogens. However, other etiologies of dwarfism, such as pituitary dwarfism, primary or secondary growth failures, hormone failures, or poor nutrition are not usually linked with deafness. EGDBD p.107-108.
Dysostosis mandibulofacial, see Treacher Collins syndrome
Ear infection, see Otitis media
Eardrum, see Perforated eardrum
Earwax, see Cerumen buildup
Ectodermal dysplasia-pancreatic insufficiency, see Johanson-Blizzard syndrome
This is retention of excess water in the body, especially during pregnancy. It can cause a conductive deafness through water in the middle ear, muffling the action of the middle ear bones. Diuretic medications can help, though with caution since, ironically, diuretics are ototoxic drugs.
An inflammation of the brain itself, distinguished from cerebral meningitis which is an inflammation of the membrane surrounding the brain. Usually caused by infective viruses (like rabies or herpes), bacteria, protozoa, worms, or even some chemicals. It is also possible for humans to be infected with equine (horse) encephalitis carried by mosquitoes. Damage is caused either directly to the nerve cells of the brain or to the sheath (myelin) around the nerve cell. If the damage involves those areas of the brain responsible for hearing, a hearing impairment may result. Common symptoms include fever, headache, drowsiness, lethargy, tremors and coma; convulsions sometimes occur, mainly in infants. Lesser symptoms may include uncoordinated movements, weakness, and unusual sensitivity of the skin. EDHD2 p.77.
Endemic cretinism, see Thyroid disorders
Erythroblastosis fetalis, see Rh incompatibility disease
Exanthema infantum or exanthema subitum, see Roseola infantum
Facio-scapulo-humeral dystrophy, see Muscular dystrophy
Falls, see Trauma
Familial nephritis, see Alport syndrome
Fechtner syndrome, see Alport syndrome
Fetal alcohol syndrome (FAS)
Reported to cause hearing loss in up to 64% of infants born to alcoholic mothers, from the ototoxic effect on the developing fetus plus malnutrition during pregnancy from the excess alcohol intake. Common characteristics include small size, narrow foreheads with a "sleepy" facial appearance, and a long, smooth upper lip; mental retardation often occurs, as does hyperactivity and speech delay. DSID p.115-117; EDHD2 p.82; EDHD p.156; EGDBD p.129-130.
A variety of illnesses and diseases are known to be able to damage the delicate hair cells in the cochlea, and sometimes other hearing-related nerve cells, from prolonged exposure to high fever temperatures. One example of this is roseola infantum (q.v.) Such sensorineural nerve damage is permanent, as most nerve cells do not regenerate themselves.
First and second branchial arch syndrome, see Goldenhar syndrome
Ocular changes, including severe myopia, cataracts and retinitus pigmentosa, nerve deafness, cutaneous atrophy, joint stiffness, muscle wasting and neurological changes including peripheral neuropathology, ataxia, epilepsy and dementia.
Familial mitral insufficiency, conductive hearing loss, short stature, and bony fusion of cervical vertebrae and carpal and tarsal bones.
Franceschetti syndrome, see Manibulofacial dystosis
Franceschetti-Klein syndrome, see Treacher Collins syndrome
Also called Friedrich disease, hereditary spinal ataxia, or recessive spinocerebellar degeneration. Inherited as an autosomal recessive characteristic, the affected gene being on chromosome 9. The basic cause is not yet established, but it may be a metabolic disease. Atrophy of specific parts of the spinal chord. Ataxia (an inability to coordinate the voluntary muscular movements) is the most obvious symptom, though they do not begin to show until around age 3, and in some cases not until puberty. Unsteadiness begins in the legs and progresses up the body, accompanied by weakness and loss of reflexes. Disturbances of eye movement and hypertrophia of the heart follow, plus diabetes in about 20% of cases. Deafness is less often seen but can accompany the other symptoms. Victims are almost always forced into a wheelchair by their early twenties, and death from heart or respiratory problems usually occurs by age 40. DSID p.121-123; EGDBD p.134-135.
Functional hearing loss
Also known as psychogenic hearing loss or hysterical hearing loss. Deafness that results from psychological or emotional factors, rather than from physical causes. Hearing is actually present, but the brain's recognition of it is psychologically blocked. Often caused by anxiety over emotional conflicts, and is involuntary; can be either partial or total. Diagnosis is sometimes complicated by the presence of a real physical hearing loss, either "overlaid" by the functional loss or in one ear while the other ear has the functional loss (unilateral functional deafness). EDHD2 p.85.
Many medical syndromes that include deafness result from mutations in one or more genes that are linked to deafness. The gene called Connexin 26 may be responsible for up to 40% of cases of inherited hearing impairment. Another gene called GJB2 can have many different deafness-causing mutations, the one called 35delG being the most common one. In 2001, researchers reported that gene DFNA15 had been linked to early deafness within a family. Many deafness-causing syndromes result from genetic mutations, and can be found throughout this paper. EDHD2 p.93.
Geniculate syndrome, see Hunt syndrome
German measles, see Rubella
Also known as Goldenhar-Gorlin syndrome, ocularauriculovertebral dysplasia, or first and second branchial arch syndrome. At birth, facial asymmetry, both external and internal ear malformations, epibulbar dermoids, preauricular appendages, vertebral anomalies, hearing defect of various degrees from near-normal to severe hearing loss (conductive type) and vision defects, including diplopia of various degrees. Inheritance is sporadic in most cases; about a 1% risk of occurrence in siblings. DSID p.130-133; EGDBD p.150.
Gregg syndrome, see Rubella
Hallgren syndrome, see Usher syndrome
Heavy metals, see Ototoxic drugs and other substances
Hereditary factors causing deafness.
There is a good short discussion of the many factors causing deafness from various hereditary causes in EGDBD p.96-98.
Hereditary nephritis, see Alport syndrome
Hereditary progressive arthro-ophthalmopathy, see Stickler syndrome
Hereditary spinal ataxia, see Friedrich ataxia
Heredopathia atactica polyneuritoformis, see Refsum syndrome
Herpes simplex virus, type II
Acquired by the infant during birth if the mother is infected. Fatal in most cases, but survivors may have hearing loss. EDHD2 p.106.
Herpes zoster auricularis, see Hunt syndrome
HIV (Human Immunodeficiency Virus), see AIDS
Also known as geniculate syndrome. Herpes zoster auricularis ("shingles") with associated facial paralysis; a viral infection of the nerves supplying certain areas of the skin. In some cases, intense pain in the region of the ear and mastoid process, paralysis of the facial nerve, hearing loss, vertigo and hyperacusia. Herpetic lesions over the mastoid process and around the external auditory canal and eardrum. EDHD p.168.
Also called mucopolysaccharidosis 2 and MPS II. A genetic defect in the metabolism of the complex sugars; the enzyme iduronate sulphatase is lacking (see also Hurler syndrome, Morquio syndrome, and Sanfilippo syndrome). X-linked recessive, so affects males only. Two types of Hunter syndrome, one milder and less progressively downhill than the other. Signs and symptoms of this syndrome include normal appearance at birth except for possible noisy breathing and umbilical hernias, both common normal childhood syndromes and so not usually alarming. At around age 2, facial features become more coarse, erupting teeth are widely spaced, the boy's growth rate slows down, and joints become stiff. The liver and spleen become enlarged. Other complications can include meningitis (q.v.), which in turn frequently leads to deafness. Death usually occurs in the late teens or early twenties from cardiac or respiratory problems. DSID p.152-155; EGDBD p.225-226.
Also called mucopolysaccharidosis 1-H, MPS I, or gargoylism. A genetic defect in the metabolism of the complex sugars; the enzyme alpha-L-iduronidase is lacking (see also Hunter syndrome, Morquio syndrome, and Sanfilippo syndrome). Affects both sexes equally and has been found in all races. Caused by a genetic defect inherited as an autosomal recessive. Appearance at birth is normal, though sometimes very large. From the early months of life, other symptoms begin to appear: coarsening of the facial features, noisy breathing accompanied by a persistently blocked and runny nose, enlargement of the liver and spleen, stiffening of the joints, progressive blindness from clouding of the corneas, acquired mental retardation, and cardiac defects. Deafness also commonly occurs from the progressive accumulation of mucopolysaccharides. DSID p.156-159; EGDBD p.225.
A condition present at birth in which high levels of bilirubin damage the cochlear nuclei in the brainstem by deposition of pigment in the gray matter (kerniciterus). The pigment apparently impairs the functioning of the cochlear nerves, causing central nerve deafness. May result from various previous diseases, including Rh incompatibility disease (q.v.). GEDPD v.2 p.25; EDHD2 p.122.
Hypoxia, see Asphyxia at birth
Hysterical hearing loss, see Functional hearing loss
Immotile cilia syndrome, see Kartagener syndrome
Infantile Refsum disease
Not to be confused with "classical" Refsum disease (q.v.), which is actually a different condition. Like Refsum disease, it is a rare genetic disorder characterized by the body's inability to metabolize and rid itself of phytanic acid, which then accumulates to ototoxic levels. It differs in being a member of a group of genetic diseases called leukodystrophies. Symptoms may include eye problems such as retinitis pigmentosis and nystagmus, decrease in muscle tone, failure to thrive, developmental delays, poor muscle coordination, enlarged liver, low cholesterol level and facial abnormalities. EDHD2 p.178.
Jervell and Lange-Nielson syndrome
Congenital sensorineural deafness with ventricular fibrillation, causing fainting and sometimes death. Affects children of either sex with bilateral conduction type deafness, presenting in infancy or early childhood repeated attacks of syncope. Seizures may begin with a piercing scream followed by pallor and then cyanosis and loss of consciousness of short duration, followed by deep sleep. Attack may result in sudden death. An autosomal recessive inheritance (genes KVLT1 and KCNE1). GEDPD v.2 p.21; EGDBD p.187-188.
Also known as ectodermal dysplasia-pancreatic insufficiency. A rare genetic condition probably inherited in an autosomal recessive way. Symptoms include unusually small and short nose, small upper jaw, and, sometimes, microcephaly. Teeth are small and widely spaced, and some may be absent altogether. Failure to thrive due to malabsorption of food from the pancreatic enzyme deficiency. Learning difficulties are also often present. Sensorineural deafness in some cases. DSID p.166-168.
Also known as Kartagener's triad (dextrocardia, bronchiectasis, and sinusitis) or immotile cilia syndrome. Onset in early infancy. Characterized by dyspnea, productive cough, recurrent respiratory infection, palpitation, otitis media, nasal speech and conductive hearing loss. No exact figures for numbers of victims, but possibly as many as 1 in 4000 births may be affected. Both sexes can be affected. DSID p.169-172; EGDBD p.190-191.
Kearns-Sayre syndrome (KSS)
A genetic (mitochondrial) condition that appears before the age of 20. Cardiac and neural abnormalities, ophthalmoplegia and retinal disease, often accompanied by short stature, mental retardation, ataxia, and sensorineural hearing loss. EGDBD p.221.
Kernicterus, see Hyperbilurbinemia
Klein-Waardenburg syndrome, see Waardenburg syndrome
Also known as Klippel-Feil anomaly (or ...sequence or ...disorder), congenital brevicollis, or cervical fusion syndrome. Incidence rate is around 1 in 40,000 live births; approximately 60% of the victims are girls. Congenital ear dysplasia, combined with cleft palate, short neck, fusion of the cervical vertebrae, and abnormalities of the brain stem and cerebrellum. Either conductive or sensorineural deafness in a small proportion of cases. DSID p.176-178; EGDBD p.192.