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Genetics Home Reference: your guide to understanding genetic conditions
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Chromosome 6

Reviewed February 2011

What is chromosome 6?

Humans normally have 46 chromosomes in each cell, divided into 23 pairs. Two copies of chromosome 6, one copy inherited from each parent, form one of the pairs. Chromosome 6 spans about 171 million DNA building blocks (base pairs) and represents between 5.5 and 6 percent of the total DNA in cells.

Identifying genes on each chromosome is an active area of genetic research. Because researchers use different approaches to predict the number of genes on each chromosome, the estimated number of genes varies. Chromosome 6 likely contains 1,000 to 1,100 genes that provide instructions for making proteins. These proteins perform a variety of different roles in the body.

Genes on chromosome 6 are among the estimated 20,000 to 25,000 total genes in the human genome.

Genetics Home Reference includes these genes on chromosome 6:

  • ALDH5A1
  • ARG1
  • ARID1B
  • ATXN1
  • BCKDHB
  • C2
  • COL9A1
  • COL11A2
  • CUL7
  • CYP21A2
  • EFHC1
  • ELOVL4
  • EPM2A
  • EYA4
  • FIG4
  • FOXC1
  • GJA1
  • GNMT
  • GTF2H5
  • HFE
  • HLA-B
  • HLA-DPB1
  • HLA-DQA1
  • HLA-DQB1
  • HLA-DRB1
  • LAMA2
  • LHFPL5
  • MOCS1
  • MUT
  • MYO6
  • NEU1
  • NHLRC1
  • PARK2
  • PEX7
  • PKHD1
  • PLAGL1
  • PLG
  • POLH
  • POLR1C
  • PRPH2
  • PSMB8
  • RAB23
  • RARS2
  • RPS10
  • RUNX2
  • SERAC1
  • SKIV2L
  • SLC17A5
  • SYNE1
  • T
  • TBP
  • TFAP2A
  • TFAP2B
  • TNXB
  • TREM2
  • WISP3
  • ZFP57

How are changes in chromosome 6 related to health conditions?

Many genetic conditions are related to changes in particular genes on chromosome 6. This list of disorders associated with genes on chromosome 6 provides links to additional information.

Genetics Home Reference includes these conditions related to genes on chromosome 6:

  • age-related macular degeneration
  • amyotrophic lateral sclerosis
  • ankylosing spondylitis
  • arginase deficiency
  • autoimmune Addison disease
  • autosomal recessive cerebellar ataxia type 1
  • Axenfeld-Rieger syndrome
  • Behçet disease
  • branchio-oculo-facial syndrome
  • Carpenter syndrome
  • celiac disease
  • Charcot-Marie-Tooth disease
  • Char syndrome
  • chordoma
  • cleidocranial dysplasia
  • Coffin-Siris syndrome
  • complement component 2 deficiency
  • congenital plasminogen deficiency
  • critical congenital heart disease
  • Dandy-Walker syndrome
  • Diamond-Blackfan anemia
  • Ehlers-Danlos syndrome
  • familial dilated cardiomyopathy
  • granulomatosis with polyangiitis
  • Graves disease
  • Hashimoto thyroiditis
  • hemochromatosis
  • Huntington disease-like syndrome
  • 21-hydroxylase deficiency
  • hypermethioninemia
  • idiopathic inflammatory myopathy
  • juvenile idiopathic arthritis
  • juvenile myoclonic epilepsy
  • Lafora progressive myoclonus epilepsy
  • LAMA2-related muscular dystrophy
  • 3-M syndrome
  • maple syrup urine disease
  • MEGDEL syndrome
  • methylmalonic acidemia
  • molybdenum cofactor deficiency
  • multiple epiphyseal dysplasia
  • multiple sclerosis
  • Nakajo-Nishimura syndrome
  • narcolepsy
  • nonsyndromic deafness
  • oculodentodigital dysplasia
  • otospondylomegaepiphyseal dysplasia
  • Parkinson disease
  • Peters anomaly
  • polycystic kidney disease
  • polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy
  • pontocerebellar hypoplasia
  • porphyria
  • progressive pseudorheumatoid dysplasia
  • psoriatic arthritis
  • Refsum disease
  • 6q24-related transient neonatal diabetes mellitus
  • retinitis pigmentosa
  • rheumatoid arthritis
  • rhizomelic chondrodysplasia punctata
  • sialic acid storage disease
  • sialidosis
  • spinocerebellar ataxia type 1
  • Stargardt macular degeneration
  • Stickler syndrome
  • succinic semialdehyde dehydrogenase deficiency
  • Treacher Collins syndrome
  • trichohepatoenteric syndrome
  • trichothiodystrophy
  • type 1 diabetes
  • vitelliform macular dystrophy
  • Weissenbacher-Zweymüller syndrome
  • xeroderma pigmentosum
  • X-linked sideroblastic anemia

Changes in the structure or number of copies of a chromosome can also cause problems with health and development. The following chromosomal conditions are associated with such changes in chromosome 6.

cancers

Duplications of genetic material in the short (p) arm of chromosome 6 have been associated with the growth and spread of several types of cancer. These duplications are somatic, which means they are acquired during a person's lifetime and are present only in certain cells. Researchers believe that some of the genes in the duplicated region on chromosome 6p are oncogenes. Oncogenes play roles in several critical cell functions, including cell division, the maturation of cells to carry out specific functions (cell differentiation), and the self-destruction of cells (apoptosis). When mutated, oncogenes have the potential to cause normal cells to become cancerous. The presence of extra copies of the oncogenes may allow cells to grow and divide in an uncontrolled way, leading to the progression and spread of cancer.

6q24-related transient neonatal diabetes mellitus

6q24-related transient neonatal diabetes mellitus, a type of diabetes that occurs in infants, is caused by the overactivity (overexpression) of certain genes in a region of the long (q) arm of chromosome 6 called 6q24. People inherit two copies of their genes, one from their mother and one from their father. Usually both copies of each gene are active, or "turned on," in cells. In some cases, however, only one of the two copies is normally turned on. Which copy is active depends on the parent of origin: some genes are normally active only when they are inherited from a person's father; others are active only when inherited from a person's mother. This phenomenon is known as genomic imprinting.

The 6q24 region includes paternally expressed imprinted genes, which means that normally only the copy of each gene that comes from the father is active. The copy of each gene that comes from the mother is inactivated (silenced) by a mechanism called methylation.

There are three ways that overexpression of paternally expressed imprinted genes in the 6q24 region can occur. About 40 percent of cases of 6q24-related transient neonatal diabetes mellitus are caused by a genetic change known as paternal uniparental disomy (UPD) of chromosome 6. In paternal UPD, people inherit both copies of the affected chromosome from their father instead of one copy from each parent. Paternal UPD causes people to have two active copies of paternally expressed imprinted genes, rather than one active copy from the father and one inactive copy from the mother.

Another 40 percent of cases of 6q24-related transient neonatal diabetes mellitus occur when the copy of chromosome 6 that comes from the father has a duplication of genetic material including the paternally expressed imprinted genes in the 6q24 region.

The third mechanism by which overexpression of genes in the 6q24 region can occur is by impaired silencing of the maternal copy of the genes (maternal hypomethylation). Approximately 20 percent of cases of 6q24-related transient neonatal diabetes mellitus are caused by maternal hypomethylation. Some people with this disorder have a genetic change in the maternal copy of the 6q24 region that prevents genes in that region from being silenced. Other affected individuals have a more generalized impairment of gene silencing involving many imprinted regions, called hypomethylation of imprinted loci (HIL). Because HIL can cause overexpression of many genes, this mechanism may account for the additional health problems that occur in some people with 6q24-related transient neonatal diabetes mellitus.

It is not well understood how overexpression of genes in the 6q24 region causes 6q24-related transient neonatal diabetes mellitus and why the condition improves after infancy. This form of diabetes is characterized by high blood sugar levels (hyperglycemia) resulting from a shortage of the hormone insulin. Insulin controls how much glucose (a type of sugar) is passed from the blood into cells for conversion to energy.

The protein produced from one gene in the 6q24 region may help control insulin secretion by beta cells in the pancreas. In addition, overexpression of this protein has been shown to stop the cycle of cell division and lead to the self-destruction of cells (apoptosis). Researchers suggest that overexpression of this gene may reduce the number of insulin-secreting beta cells or impair their function in affected individuals.

Lack of sufficient insulin results in the signs and symptoms of diabetes mellitus. In individuals with 6q24-related transient neonatal diabetes mellitus, these signs and symptoms are most likely to occur during times of physiologic stress, including the rapid growth of infancy, childhood illnesses, and pregnancy. Because insulin acts as a growth promoter during early development, a shortage of this hormone may account for the slow growth before birth (intrauterine growth retardation) seen in 6q24-related transient neonatal diabetes mellitus.

other chromosomal conditions

Other changes in the number or structure of chromosome 6 can have a variety of effects, including delayed growth and development, intellectual disability, distinctive facial features, birth defects, and other health problems. Changes to chromosome 6 may include deletions or duplications of genetic material in the short (p) or long (q) arm of the chromosome in each cell, or a circular structure called ring chromosome 6. Ring chromosomes occur when a chromosome breaks in two places and the ends of the chromosome arms fuse together to form a circular structure.

Is there a standard way to diagram chromosome 6?

Geneticists use diagrams called ideograms as a standard representation for chromosomes. Ideograms show a chromosome's relative size and its banding pattern. A banding pattern is the characteristic pattern of dark and light bands that appears when a chromosome is stained with a chemical solution and then viewed under a microscope. These bands are used to describe the location of genes on each chromosome.

Ideogram of chromosome 6
See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.

Where can I find additional information about chromosome 6?

You may find the following resources about chromosome 6 helpful. These materials are written for the general public.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What glossary definitions help with understanding chromosome 6?

apoptosis ; cancer ; cell ; cell division ; chromosome ; diabetes ; diabetes mellitus ; differentiation ; disability ; DNA ; duplication ; expressed ; gene ; gene silencing ; glucose ; high blood sugar ; hormone ; hyperglycemia ; imprinting ; inherit ; inherited ; insulin ; intrauterine growth retardation ; maternal ; methylation ; neonatal ; pancreas ; progression ; promoter ; protein ; ring chromosomes ; secretion ; stress ; transient ; uniparental disomy

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).

References

  • Andrieux J, Devisme L, Valat AS, Robert Y, Frnka C, Savary JB. Prenatal diagnosis of ring chromosome 6 in a fetus with cerebellar hypoplasia and partial agenesis of corpus callosum: case report and review of the literature. Eur J Med Genet. 2005 Apr-Jun;48(2):199-206. Epub 2005 Feb 12. Review. (http://www.ncbi.nlm.nih.gov/pubmed/16053913?dopt=Abstract)
  • Diatloff-Zito C, Nicole A, Marcelin G, Labit H, Marquis E, Bellanné-Chantelot C, Robert JJ. Genetic and epigenetic defects at the 6q24 imprinted locus in a cohort of 13 patients with transient neonatal diabetes: new hypothesis raised by the finding of a unique case with hemizygotic deletion in the critical region. J Med Genet. 2007 Jan;44(1):31-7. Epub 2006 Sep 13. (http://www.ncbi.nlm.nih.gov/pubmed/16971482?dopt=Abstract)
  • Docherty LE, Poole RL, Mattocks CJ, Lehmann A, Temple IK, Mackay DJ. Further refinement of the critical minimal genetic region for the imprinting disorder 6q24 transient neonatal diabetes. Diabetologia. 2010 Nov;53(11):2347-51. doi: 10.1007/s00125-010-1853-2. Epub 2010 Jul 30. (http://www.ncbi.nlm.nih.gov/pubmed/20668833?dopt=Abstract)
  • Ensembl Human Map View: Chromosome 6 (http://www.ensembl.org/Homo_sapiens/Location/Chromosome?chr=6;r=6:1-170805979)
  • Gene Review: Diabetes Mellitus, 6q24-Related Transient Neonatal (http://www.ncbi.nlm.nih.gov/books/NBK1534)
  • Gilbert F. Chromosome 6. Genet Test. 2002 Winter;6(4):341-58. (http://www.ncbi.nlm.nih.gov/pubmed/12537662?dopt=Abstract)
  • Lin RJ, Cherry AM, Chen KC, Lyons M, Hoyme HE, Hudgins L. Terminal deletion of 6p results in a recognizable phenotype. Am J Med Genet A. 2005 Jul 15;136(2):162-8. Review. (http://www.ncbi.nlm.nih.gov/pubmed/15940702?dopt=Abstract)
  • Map Viewer: Genes on Sequence (http://www.ncbi.nlm.nih.gov/mapview/maps.cgi?ORG=human&MAPS=ideogr,ugHs,genes&CHR=6)
  • Mungall AJ, Palmer SA, Sims SK, Edwards CA, Ashurst JL, Wilming L, Jones MC, Horton R, Hunt SE, Scott CE, Gilbert JG, Clamp ME, Bethel G, Milne S, Ainscough R, Almeida JP, Ambrose KD, Andrews TD, Ashwell RI, Babbage AK, Bagguley CL, Bailey J, Banerjee R, Barker DJ, Barlow KF, Bates K, Beare DM, Beasley H, Beasley O, Bird CP, Blakey S, Bray-Allen S, Brook J, Brown AJ, Brown JY, Burford DC, Burrill W, Burton J, Carder C, Carter NP, Chapman JC, Clark SY, Clark G, Clee CM, Clegg S, Cobley V, Collier RE, Collins JE, Colman LK, Corby NR, Coville GJ, Culley KM, Dhami P, Davies J, Dunn M, Earthrowl ME, Ellington AE, Evans KA, Faulkner L, Francis MD, Frankish A, Frankland J, French L, Garner P, Garnett J, Ghori MJ, Gilby LM, Gillson CJ, Glithero RJ, Grafham DV, Grant M, Gribble S, Griffiths C, Griffiths M, Hall R, Halls KS, Hammond S, Harley JL, Hart EA, Heath PD, Heathcott R, Holmes SJ, Howden PJ, Howe KL, Howell GR, Huckle E, Humphray SJ, Humphries MD, Hunt AR, Johnson CM, Joy AA, Kay M, Keenan SJ, Kimberley AM, King A, Laird GK, Langford C, Lawlor S, Leongamornlert DA, Leversha M, Lloyd CR, Lloyd DM, Loveland JE, Lovell J, Martin S, Mashreghi-Mohammadi M, Maslen GL, Matthews L, McCann OT, McLaren SJ, McLay K, McMurray A, Moore MJ, Mullikin JC, Niblett D, Nickerson T, Novik KL, Oliver K, Overton-Larty EK, Parker A, Patel R, Pearce AV, Peck AI, Phillimore B, Phillips S, Plumb RW, Porter KM, Ramsey Y, Ranby SA, Rice CM, Ross MT, Searle SM, Sehra HK, Sheridan E, Skuce CD, Smith S, Smith M, Spraggon L, Squares SL, Steward CA, Sycamore N, Tamlyn-Hall G, Tester J, Theaker AJ, Thomas DW, Thorpe A, Tracey A, Tromans A, Tubby B, Wall M, Wallis JM, West AP, White SS, Whitehead SL, Whittaker H, Wild A, Willey DJ, Wilmer TE, Wood JM, Wray PW, Wyatt JC, Young L, Younger RM, Bentley DR, Coulson A, Durbin R, Hubbard T, Sulston JE, Dunham I, Rogers J, Beck S. The DNA sequence and analysis of human chromosome 6. Nature. 2003 Oct 23;425(6960):805-11. (http://www.ncbi.nlm.nih.gov/pubmed/14574404?dopt=Abstract)
  • Pivnick EK, Qumsiyeh MB, Tharapel AT, Summitt JB, Wilroy RS. Partial duplication of the long arm of chromosome 6: a clinically recognisable syndrome. J Med Genet. 1990 Aug;27(8):523-6. Review. (http://www.ncbi.nlm.nih.gov/pubmed/2213846?dopt=Abstract)
  • Santos GC, Zielenska M, Prasad M, Squire JA. Chromosome 6p amplification and cancer progression. J Clin Pathol. 2007 Jan;60(1):1-7. Epub 2006 Jun 21. Review. (http://www.ncbi.nlm.nih.gov/pubmed/16790693?dopt=Abstract)
  • Temple IK, Shield JP. 6q24 transient neonatal diabetes. Rev Endocr Metab Disord. 2010 Sep;11(3):199-204. doi: 10.1007/s11154-010-9150-4. Review. (http://www.ncbi.nlm.nih.gov/pubmed/20922569?dopt=Abstract)
  • UCSC Genome Browser: Statistics (http://genome.cse.ucsc.edu/goldenPath/stats.html)
  • Urban M, Bommer C, Tennstedt C, Lehmann K, Thiel G, Wegner RD, Bollmann R, Becker R, Schulzke I, Körner H. Ring chromosome 6 in three fetuses: case reports, literature review, and implications for prenatal diagnosis. Am J Med Genet. 2002 Mar 1;108(2):97-104. Review. (http://www.ncbi.nlm.nih.gov/pubmed/11857558?dopt=Abstract)
  • Zherebtsov MM, Klein RT, Aviv H, Toruner GA, Hanna NN, Brooks SS. Further delineation of interstitial chromosome 6 deletion syndrome and review of the literature. Clin Dysmorphol. 2007 Jul;16(3):135-40. Review. (http://www.ncbi.nlm.nih.gov/pubmed/17551325?dopt=Abstract)

 

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: February 2011
Published: October 20, 2014