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ETIOLOGIES

Some conditions (in the school-aged population) on the Deafblind census are listed below.  Please click on the name of any condition that is in maroon and underlined to get more detailed information.

Specific syndromes caused by altered genes or chromosomes:

  • Usher Syndrome - MedicalUsher Syndrome - Educational
  • CHARGE SyndromePhoto of girls
  • Stickler Syndrome
  • Marshall Syndrome
  • Down Syndrome
  • Cornelia DeLange Syndrome
  • Cockayne Syndrome
  • Goldenhar Syndrome
  • Apert Syndrome
  • Crouzon Syndrome
  • Hurler Syndrome (mucopolysaccharidosis type I)
  • Maroteaux-Lamy Syndrome (mucopolysaccharidosis type VI)
  • Neurofibromatosis type 1
  • Turner Syndrome
  • Wolf Hirschhorn Syndrome
  • Waardenburg Syndrome
  • Pallister-Killian Syndrome
  • Kearnes-Sayres Syndrome
  • Lenz-Majewski Hyperostosis
  • Infantile Refsum Syndrome
  • Chromosome deletion syndromes

Sometimes conditions are listed as syndromes but they are actually just part of many other syndromes.  The following are listed on the census as causes of deafblindness but they are actually just one part of something else that may not have been fully described.

  • Pierre Robin sequence
  • Peter's Anomaly
  • Hydrocephaly
  • Microcephaly

Nongenetic conditions such as those caused by infection, injury, chemicals, or tumors.

  • CMV (cytomegalovirus) - prenatal infectionPhoto of boys
  • Toxoplasmosis - prenatal infection
  • Meningitis/encephalitis - any time after birth
  • Brain tumors
  • Chemotherapy
  • Head injury
  • Stroke
  • Asphyxia (lack of oxygen)
  • Complications of prematurity
  • Fetal alcohol syndrome
  • Maternal drug use

Some conditions, like Peter's Anomaly or hydrocephalus, are descriptions of conditions which may be present in many different syndromes but do not, by themselves, constitute a syndrome.

Medical terms you may run across:

  • Etiology is a medical term meaning the cause of a condition.
  • Chromosomal means that a large enough section of a chromosome is missing or rearranged so that it can be seen under a microscope.  The abnormal section may represent many genes.  Each cell contains 46 chromosomes in 23 pairs.  One of each pair comes from the mother and the other from the father.  Each chromosome is a long coiled double helix strand made up of DNA.
  • Genetic means that the condition is inherited through genes passed on from the parents.  Genes are small sections of chromosomes.
  • Congenital means "present at birth."  This terms says nothing about the cause.  It could have been caused by a problem during pregnancy. It could have been caused by a chromosome problem or by a genetic defect.
  • Perinatal means around the time of delivery.
  • Neonatal means the first couple of weeks after birth.
  • Acquired or adventitious means that the condition was not present at birth but happened or at least showed up later.  This means any time from birth to death.
  • Environmental means the cause for the condition was not inborn.  It might be from an injury, an infection, drugs, etc.

The non-genetic conditions may be acquired any time from pregnancy to old age. For instance, some prenatal infections like Rubella and CMV (cytomegalovirus) are well-known to cause deafblindness while treatment for cancer involving chemotherapy and radiation only occasionally causes dual sensory loss.  Sometimes a person with a genetic hearing loss may lose eyesight due to an accident or a person who is blind may become deaf due to meningitis.

Resources:

  Two general resources should be helpful to those seeking more information:
  • http://nationaldb.orgOpen in new window. Link to a different web site.  DB-Link is a national clearinghouse for information on deafblindness. Voice: 800.438.9376  TTY: 800.854.7013   Articles may be available in full text online which you can read or download or you can call a specialist to complete a search for you.
  • http://www.kumc.edu/gec/support/Open in new window. Link to a different web site.  The Genetics Education Center at the Kansas University School of Medicine  has a wealth of information about genetics and links to information about individual syndromes.  Not all syndromes are included and more information may be available elsewhere.

You may contact Dr. Sandra Davenport, a pediatric geneticist with the MN DeafBlind Project if you need further assistance (952.831.5522, slhdaven@tc.umn.edu).

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