2p15-16.1 microdeletion syndrome

2p15-16.1 microdeletion is a rare genetic disorder caused by a small deletion in the short arm of human chromosome 2. First described in two patients in 2007,[1] by 2013 only 21 (missing reference for the other ~17 patients) people have been reported as having the disorder in the medical literature.[2][3][4][5]

Clinical characteristics

Only 21 patients with 2p15-16.1 microdeletion have been described as of 2013. The clinical similarities between the individuals resulted in the classification of a new genetic syndrome.[1][2][3] The shared clinical features include moderate to severe intellectual disability and similar facial features including telecanthus, drooping eyelids, downslanting, short palpebral fissures, a prominent nasal bridge, high palate with long, smooth philtrum and an everted lower lip. Some of the patients also had feeding problems in infancy, microcephaly, optic nerve hypoplasia and hydronephrosis, wide-spaced nipples, short stature, cortical dysplasia, camptodactyly and pigeon toe.[1][2][3]

Description of deletion

Human chromosome 2. The short arm (designated by the letter p, from petit) where the deletion occurs is to the top

Three of the patients reported had a consistent proximal breakpoint on chromosome 2, but varying distal breakpoints.[1][2] The patients have 2p15–16.1 deletions of 5.7 megabases (Mb), 4.5 Mb, 3.9 Mb, 3.35Mb 3.3Mb and 570 kilobases, respectively.[4] In all 21 patients the deletions are de novo — neither parent possessed nor transmitted the mutation to the affected individual. One patient is a genetic mosaic, having some cells with the deletion and others without.[2]

Affected genes

The largest deletion encompasses approximately 15 protein-coding genes, 6 pseudogenes and a number of other as yet uncharacterised candidates, including:[2][6]

References

  1. 1 2 3 4 Rajcan-Separovic E, Harvard C, Liu X, McGillivray B, Hall JG, Qiao Y, Hurlburt J, Hildebrand J, Mickelson EC, Holden JJ, Lewis ME (2007). "Clinical and molecular cytogenetic characterisation of a newly recognised microdeletion syndrome involving 2p15-16.1.". J Med Genet. 44 (4): 269–76. doi:10.1136/jmg.2006.045013. PMC 2598046Freely accessible. PMID 16963482.
  2. 1 2 3 4 5 6 de Leeuw N, Pfundt R, Koolen DA, Neefs I, Scheltinga I, Mieloo H, Sistermans EA, Nillesen W, Smeets DF, de Vries BB, Knoers NV (2008). "A newly recognised microdeletion syndrome involving 2p15p16.1: narrowing down the critical region by adding another patient detected by genome wide tiling path array comparative genomic hybridisation analysis". J Med Genet. 45 (2): 122–4. doi:10.1136/jmg.2007.054049. PMID 18245392.
  3. 1 2 3 Chabchoub E, Vermeesch JR, de Ravel T, de Cock P, Fryns JP (2008). "The facial dysmorphy in the newly recognised microdeletion 2p15-p16.1 refined to a 570 kb region in 2p15". J Med Genet. 45 (3): 189–92. doi:10.1136/jmg.2007.056176. PMID 18310269.
  4. 1 2 Liang JS, Shimojima K, Ohno K, Sugiura C, Une Y, Ohno K, et al. (2009). "A newly recognised microdeletion syndrome of 2p15-16.1 manifesting moderate developmental delay, autistic behaviour, short stature, microcephaly, and dysmorphic features: a new patient with 3.2 Mb deletion.". J Med Genet. 46 (9): 645–7. doi:10.1136/jmg.2008.059220. PMID 19724011.
  5. ↑ Félix TM, Petrin AL, Sanseverino MT, Murray JC (2010). "Further characterization of microdeletion syndrome involving 2p15-p16.1.". Am J Med Genet A. 152A (10): 2604–8. doi:10.1002/ajmg.a.33612. PMC 2946431Freely accessible. PMID 20799320.
  6. ↑ "2p15-16.1 microdeletion syndrome". Wellcome Trust Sanger Institute. Retrieved 24 May 2011.

External links

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