World Library  
Flag as Inappropriate
Email this Article

Pallister-Killian syndrome

Article Id: WHEBN0026287313
Reproduction Date:

Title: Pallister-Killian syndrome  
Author: World Heritage Encyclopedia
Language: English
Subject: Chromosome, List of congenital disorders, Chromosome 12 (human), Tetrasomy, 12P
Publisher: World Heritage Encyclopedia

Pallister-Killian syndrome

Pallister-Killian syndrome
Classification and external resources
ICD-10 9 OMIM 601803

Pallister–Killian syndrome (also tetrasomy 12p mosaicism or Pallister mosaic aneuploidy syndrome) is an extremely rare genetic disorder occurring in humans. Pallister-Killian occurs due to the presence of the anomalous extra isochromosome 12p, the short arm of the twelfth chromosome. This leads to the development of tetrasomy 12p.[1] Because not all cells have the extra isochromosome, Pallister-Killian is a mosaic condition.

It was first described by Philip Pallister in 1977 and further researched by Maria Teschler-Nicola and Wolfgang Killian in 1981.[2]


Characteristics include varying degrees of developmental disability, epilepsy, hypotonia, and both hypopigmentation and hyperpigmentation. Patients also exhibit a distinctive facial structure, characterized by high foreheads, sparse hair on the temple, a wide space between the eyes, epicanthal folds, and a flat nose. Vision and hearing impairments may occur. Patients may also exhibit congenital heart defects, gastroesophageal reflux, cataracts, and supernumerary nipples. Diaphragm problems seen in newborns can lead to death shortly after birth.

As patients pass into adolescence, the syndrome is characterized by a coarse and flat face, macroglossia prognathia, inverted lower lip, and psychomotor retardation with muscular hypertonia and contractures.


Pallister-Killian does not appear to be hereditary. Some research has suggested that the presence of the extra chromosome may be linked to premeiotic mitotic errors, both maternally and paternally. Several theories regarding to mechanism of this formation have been introduced.[3][4]


The isochromosome can be primarily detected in samples of skin fibroblasts, as well as in chorionic villus and amniotic fluid cell samples.[2] Very rarely, it can also be detected in blood lymphocytes.[4] It is also possible to detect the isochromosome in circulating lymphocytes, as well as other amniotic and placental samples. There is no strict limit as to where the isochromosome can be found. However, it is often unlikely that these samples will be tested when the blood karyotype is normal.[5]

Using an ultrasound, Pallister-Killian may be diagnosed through observation of hypertelorism, broad neck, shorts limbs, abnormal hands or feet, diaphragmatic hernia, and hydramnios. Once born, a child may be diagnosed by observation of the syndrome's distinct facial features.

See also


External links

  • PKS Kids - The non-profit organization for Pallister-Killian Syndrome
  • PKS Support Yahoo Group
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.