Weissenbacher–Zweymüller syndrome

Weissenbacher–Zweymüller syndrome
Synonyms
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Field
Symptoms
Complications
Onset
Duration
Types
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Weissenbacher–Zweymuller syndrome (WZS), also called Pierre-Robin syndrome with fetal chondrodysplasia,<ref name=omim/> is an autosomal recessive<ref name="pmid9805126"/> congenital disorder, linked to mutations (955 gly -> glu) in the COL11A2 gene (located on chromosomal position 6p21.3), which codes for the α₂ strand of collagen type XI.<ref name=omim>Online Mendelian Inheritance in Man (OMIM) 120290 </ref><ref name="pmid9805126">,

 Heterozygous glycine substitution in the COL11A2 gene in the original patient with the Weissenbacher-Zweymüller syndrome demonstrates its identity with heterozygous OSMED (nonocular Stickler syndrome), 
 Am. J. Med. Genet., 
 1998,
 Vol. 80(Issue: 2),
 pp. 115–20,
 DOI: <115::AID-AJMG5>3.0.CO;2-O 10.1002/(SICI)1096-8628(19981102)80:2<115::AID-AJMG5>3.0.CO;2-O,
 PMID: 9805126,</ref> It is a collagenopathy, types II and XI disorder.

Presentation

It causes facial abnormalities, skeletal malformation and occasionally neural tube defects; the skeletal disfigurements resolve to a degree in the course of development.

Mutations in different parts of the gene may lead to deafness or Stickler syndrome type III (eye problems: myopia, retinal detachment and skeletal abnormalities).

Infants and children: Infants that are born with Weissenbacher-Zweymüller syndrome usually have short bones in their arms and legs. <ref>Genetics Home Reference. (2016). Retrieved from U.S. National Library of Medicine : https://ghr.nlm.nih.gov/condition/weissenbacher-zweymuller-syndrome</ref> The thigh and upper arm bones are wider than usual resulting in a dumbbell-shape while the bones of the vertebrae may be abnormal.<ref>Genetics Home Reference. (2016). Retrieved from U.S. National Library of Medicine : https://ghr.nlm.nih.gov/condition/weissenbacher-zweymuller-syndrome</ref> Typical abnormal facial features can be wide-set protruding eyes (hypertelorism), a small and upturned nose with a flat bridge, small jaw (micrognathia) and a cleft palate. Some infants have high-frequency hearing loss.<ref>Genetics Home Reference. (2016). Retrieved from U.S. National Library of Medicine : https://ghr.nlm.nih.gov/condition/weissenbacher-zweymuller-syndrome</ref> Infants may also exhibit a psychomotor delay.<ref>OSMED, Heterozygous. (2006). Retrieved from National Organization for Rare Disorders: http://rarediseases.org/rare-diseases/osmed-heterozygous </ref> After the period of growth deficiency the individual makes improvements in bone growth leading to a normal physical development around age 5 or 6.<ref>OSMED, Heterozygous. (2006). Retrieved from National Organization for Rare Disorders: http://rarediseases.org/rare-diseases/osmed-heterozygous </ref>

Adults: Many with Weissenbacher-Zweymüller syndrome have a catch-up growth phase causing the adults to not be unusually short. Many adults still will have hearing loss and typical abnormal facial features of Weissenbacher-Zweymüller syndrome. <ref>Genetics Home Reference. (2016). Retrieved from U.S. National Library of Medicine : https://ghr.nlm.nih.gov/condition/weissenbacher-zweymuller-syndrome</ref>

Causes

Dominant genetic disorders can be caused by just a single copy of an abnormal gene. This abnormal gene can be the result of being inherited from either parent or be a new mutation.<ref>OSMED, Heterozygous. (2006). Retrieved from National Organization for Rare Disorders: http://rarediseases.org/rare-diseases/osmed-heterozygous </ref> Most cases are caused by a de novo (new) mutation in the gene that occurs during the formation of the egg or sperm. These cases occur when there is no history of the disorder in the family. The COL11A2 gene is responsible for providing instructions on making one component of the type XI collagen. <ref>Genetics Home Reference. (2016). Retrieved from U.S. National Library of Medicine : https://ghr.nlm.nih.gov/condition/weissenbacher-zweymuller-syndrome</ref> Type XI collagen is a complex molecule that helps give structure and strength to the connective tissues.<ref>Genetics Home Reference. (2016). Retrieved from U.S. National Library of Medicine : https://ghr.nlm.nih.gov/condition/weissenbacher-zweymuller-syndrome</ref> Collagen is found in bone. It is also found in cartilage that makes up most of the skeleton during early development. The mutation of COL11A2 in Weissenbacher-Zweymüller syndrome disrupts the assembly of the type XI collagen molecules.<ref>Genetics Home Reference. (2016). Retrieved from U.S. National Library of Medicine : https://ghr.nlm.nih.gov/condition/weissenbacher-zweymuller-syndrome</ref> The malfunctioning collagen weakens the connective tissue causing impaired bone development. <ref>Genetics Home Reference. (2016). Retrieved from U.S. National Library of Medicine : https://ghr.nlm.nih.gov/condition/weissenbacher-zweymuller-syndrome</ref> COL11A2 is also associated with autosomal dominant non-syndromic hearing loss (ADNSHL).<ref>Kim, S., Park, H., Sagong, B. et al. Genes Genom (2016). doi:10.1007/s13258-016-0440-4 </ref> All mutations of COL11A2 in ADNSHL are missense mutations.<ref>Kim, S., Park, H., Sagong, B. et al. Genes Genom (2016). doi:10.1007/s13258-016-0440-4 </ref>

Diagnosis

Weissenbacher-Zweymüller syndrome is diagnosed upon a thorough clinical evaluation, detailed patient history, identification of characteristic symptom and a variety of specialized tests which includes x-rays. <ref>OSMED, Heterozygous. (2006). Retrieved from National Organization for Rare Disorders: http://rarediseases.org/rare-diseases/osmed-heterozygous </ref>

Treatment

There is no cure as of now. Treatment is directed towards the specific symptoms that are present in each individual. <ref>OSMED, Heterozygous. (2006). Retrieved from National Organization for Rare Disorders: http://rarediseases.org/rare-diseases/osmed-heterozygous </ref> Individuals with hearing loss are able to get treated with hearing aids.

Epidemiology

Weissenbacher-Zweymüller syndrome affects males and females in the same numbers. About 30 cases have been reported in medical literature. <ref>OSMED, Heterozygous. (2006). Retrieved from National Organization for Rare Disorders: http://rarediseases.org/rare-diseases/osmed-heterozygous </ref>This disorder can be underdiagnosed causing no true frequency in the population.<ref>OSMED, Heterozygous. (2006). Retrieved from National Organization for Rare Disorders: http://rarediseases.org/rare-diseases/osmed-heterozygous </ref> Only 30 cases have been reported in medical literature. <ref>OSMED, Heterozygous. (2006). Retrieved from National Organization for Rare Disorders: http://rarediseases.org/rare-diseases/osmed-heterozygous </ref>

Eponym

It was first characterized in 1964 by G. Weissenbacher and Ernst Zweymüller.<ref>synd/1776 at Who Named It?</ref><ref>,

 [Gleichzeitiges Vorkommen eines Syndroms von Pierre Robin und einer fetalen Chondrodysplasie.], 
 Monatsschrift für Kinderheilkunde, 
 1964,
 Vol. 112,
 pp. 315–7,
 
 PMID: 14234962,</ref>

External links

• Pierre Robin syndrome with fetal chondrodysplasia; Weissenbacher-Zweymüller syndrome at NIH's Office of Rare Diseases

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Weissenbacher–Zweymüller syndrome

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