Chromosome 15

Chromosome 15 is one of the 23 pairs of chromosomes in humans. 

People normally have two copies of this chromosome. 

Chromosome 15 spans about 102 million base pairs which is the building material of DNA, and represents between 3% and 3.5% of the total DNA in cells. 

Chromosome 15 is an acrocentric

It has a very small short arm, the “p” arm, for “petite”, which contains few protein coding genes among its 19 million base pairs. 

It has a larger long arm (the “q” arm) that is gene rich, spanning about 83 million base pairs.

The human leukocyte antigen gene for β2-microglobulin is found on chromosome 15, as well as the FBN1 gene, coding for both fibrillin-1, a protein critical to the proper functioning of connective tissue.and aprosin, a small protein produced from part of the transcribed FBN1 gene mRNA, which is involved in fat metabolism.

The following is a partial list of genes on human chromosome 15.

AAGAB: alpha- and gamma-adaptin binding protein

ACSBG1: encoding enzyme Acyl-CoA Synthetase, Bubblegum Family, member 1

ARHGAP11B: a human-specific gene encoding the Rho GTPase activating protein 11B, that amplifies basal progenitors, controls neural progenitor proliferation, and contributes to neocortex folding.

ARPIN: encoding protein Actin related protein 2/3 complex inhibitor

ARPP-19: encoding protein cAMP-regulated phosphoprotein 19

B2MR: encoding protein Beta-2-microglobulin regulator

C15orf15: encoding protein Probable ribosome biogenesis protein RLP24

C15orf32: encoding protein Uncharacterized protein C15orf32

C15orf54: encoding protein Chromosome 15 Open Reading Frame 54

CAPN3: Calpain 3 (limb-girdle muscular dystrophy type 2A)

CELF6: encoding protein Cugbp elav-like family member 6

CHP: Calcium binding protein P22

CHSY1: Chondroitin sulfate synthase 1

CLK3: CDC like kinase 3

ClpX: encoding enzyme ATP-dependent Clp protease ATP-binding subunit clpX-like, mitochondrial

COMMD4: encoding protein COMM domain-containing protein 4

CPEB1: Cytoplasmic polyladenylation element binding protein 1


ELL3: encoding protein Elongation factor RNA polymerase II-like 3

FAH: fumarylacetoacetate hydrolase (fumarylacetoacetase)

FAM214A: encoding protein Protein FAM214A

FBN1: fibrillin 1 (Marfan syndrome)

FOXB1: encoding protein Forkhead box B1

GATM: Glycine aminotransferase, mitochondrial

GCHFR: GTP cyclohydrolase 1 feedback regulatory protein

GLC1I: encoding protein Glaucoma 1, open angle, i

GLCE: D-glucuronyl C5-epimerase

GOLGA8H: encoding protein Golgin subfamily A member 8H


HEXA: hexosaminidase A (alpha polypeptide)(Tay–Sachs disease)

HMG20A: encoding protein High mobility group protein 20A

IDDM3 encoding protein Insulin dependent diabetes mellitus 3

IMP3: encoding protein U3 small nucleolar ribonucleoprotein protein IMP3

ITPKA: encoding enzyme Inositol-trisphosphate 3-kinase A

IVD: isovaleryl Coenzyme A dehydrogenase

KATNBL1: encoding protein KATNBL1

LARP6 encoding protein La-related protein 6 also known as acheron or La ribonucleoprotein domain family member 6 (LARP6),

LCMT2: encoding enzyme Leucine carboxyl methyltransferase 2

LINC00926 encoding protein Long intergenic non-protein coding RNA 926

MESDC2: encoding protein LDLR chaperone MESD

MESP1: encoding protein Mesoderm posterior 1 homolog (mouse)

MFAP1: encoding protein Microfibrillar-associated protein 1

MCPH4: microcephaly, primary autosomal recessive 4

MIR7-2: encoding protein MicroRNA 7-2

MIR627: encoding protein MicroRNA 627

NIPA2: encoding protein Non-imprinted in Prader-Willi/Angelman syndrome region protein 2

OCA2: oculocutaneous albinism II (pink-eye dilution homolog, mouse)

PDCD7: encoding protein Programmed cell death protein 7

PIF1: encoding protein PIF1 5′-to-3′ DNA helicase

PML: promyelocytic leukemia protein (involved in t(15,17) with RARalpha, predominant cause of acute promyelocytic leukemia.

POTEB: encoding protein POTE ankyrin domain family, member B

PTPLAD1: encoding enzyme Protein tyrosine phosphatase-like protein PTPLAD1

PYGO1: encoding protein Pygopus homolog 1 (Drosophila)

RAD51: RAD51 homolog (RecA homolog, E. coli) (S. cerevisiae)

RMDN3: encoding protein Regulator of microtubule dynamics protein 3

RNR3: encoding RNA, ribosomal 45S cluster 3

RTF1: encoding protein Rtf1, Paf1/RNA polymerase II complex component, homolog (S. cerevisiae)

SCAMP2: encoding protein Secretory carrier-associated membrane protein 2

SCAMP5: encoding protein Secretory carrier-associated membrane protein 5

SCZD10: encoding protein Schizophrenia disorder 10 (periodic catatonia)

SCAPER: S-phase CyclinA Associated Protein residing in the Endoplasmic Reticulum

SENP8: encoding enzyme Sentrin-specific protease 8

SERF2: encoding protein Small EDRK-rich factor 2

SLC24A5: the gene responsible for at least 1/3 of the skin color differences between races, expressed in the brain and the nervous system

SNAPC5: encoding protein snRNA-activating protein complex subunit 5

SPN1: encoding protein Snurportin1

STRC: stereocilin

SUHW4: encoding protein Zinc finger protein 280D

SYNM: encoding protein Synemin

TEX9: encoding protein Testis-expressed protein 9

TGFBR2: location 3p24.2-p25 due to a inactivation mutation

TMC3: encoding protein Transmembrane channel like 3

TMCO5A: encoding protein Transmembrane and coiled-coil domains 5A

TMED3: encoding protein Transmembrane p24 trafficking protein 3

UBE2Q2: encoding protein Ubiquitin conjugating enzyme e2 q2

UBE3A: ubiquitin protein ligase E3A (human papilloma virus E6-associated protein, Angelman syndrome)


VPS39: encoding protein hVam6p/Vps39-like protein

ZNF592: encoding protein Zinc finger protein 592

UNC13C: encoding protein unc-13 homolog C

The following conditions are caused by mutations in chromosome 15. 

Angelman syndrome and Prader–Willi syndrome: involve a loss of gene activity in the same part of chromosome 15, the 15q11.2-q13.1 region. 

The main characteristics of Angelman syndrome are severe intellectual disability, ataxia, lack of speech, and excessively happy demeanor. 

Angelman syndrome results from a loss of gene activity in a specific part of chromosome 15, the 15q11-q13 region. 

This region contains a gene called UBE3A that, when mutated or absent, likely causes the characteristic features of this condition. 

People normally have two copies of the UBE3A gene, one from each parent. 

Both copies of this gene are active in many of the body’s tissues. In the brain, however, only the copy inherited from a person’s mother is active. 

If the maternal copy is lost because of a chromosomal change or a gene mutation, a person will have no working copies of the UBE3A gene in the brain.

In most cases, 70%, people with Angelman syndrome have a deletion in the maternal copy of chromosome 15. 

This chromosomal change deletes the region of chromosome 15 that includes the UBE3A gene. 

Because the copy of the UBE3A gene inherited from a person’s father is normally inactive in the brain, a deletion in the maternal chromosome 15 results in no active copies of the UBE3A gene in the brain.

In 3% to 7% of cases, Angelman syndrome occurs when a person has two copies of the paternal chromosome 15 instead of one copy from each parent: paternal uniparental disomy (UPD). 

People with paternal UPD for chromosome 15 have two copies of the UBE3A gene, but they are both inherited from the father and are therefore inactive in the brain.

About 10% of Angelman syndrome cases are caused by a mutation in the UBE3A gene, and another 3% result from a defect in the DNA region that controls the activation of the UBE3A gene and other genes on the maternal copy of chromosome 15. 

In a small percentage of cases, Angelman syndrome may be caused by a chromosomal rearrangement called a translocation or by a mutation in a gene other than UBE3A. 

These genetic changes can abnormally inactivate the UBE3A gene.

Prader–Willi syndrome

The main characteristics of PWS include extreme, insatiable appetite, mild to moderate developmental delay, hypogonadism resulting in delayed to no puberty, and hypotonia. 

Prader-Willi syndrome is caused by the loss of active genes in a specific part of chromosome 15, the 15q11-q13 region. 

People normally have two copies of this chromosome in each cell, one copy from each parent. 

Prader–Willi syndrome occurs when the paternal copy is partly or entirely missing.

In about 70% of cases, Prader–Willi syndrome occurs when the 15q11-q13 region of the paternal chromosome 15 is deleted. 

The genes in this region are normally active on the paternal copy of the chromosome and are inactive on the maternal copy. 

Therefore, a person with a deletion in the paternal chromosome 15 will have no active genes in this region.

In about 25% of cases, a person with Prader–Willi syndrome has two maternal copies of chromosome 15 in each cell instead of one copy from each parent. 

This phenomenon is called maternal uniparental disomy. 

Because some genes are normally active only on the paternal copy of this chromosome, a person with two maternal copies of chromosome 15 will have no active copies of these genes.

In a small percentage of cases the condition is caused by an abnormality in the DNA region that controls the activity of genes on the paternal chromosome 15. 

Because patients almost always have difficulty reproducing, Prader–Willi syndrome is generally not hereditary.

A specific chromosomal change called an isodicentric chromosome 15 (IDIC15) can affect growth and development. 

The patient possesses an “extra” chromosome. 

This small extra chromosome is made up of genetic material from chromosome 15 that has been abnormally duplicated and attached end-to-end. 

In some cases, the extra chromosome is very small and has no effect on a person’s health. 

A larger isodicentric chromosome 15 can result in hypotonia, intellectual disability, seizures, and behavioral problems.

Signs and symptoms of autism have also been associated with the presence of an isodicentric chromosome 15.

A number or structural changes of chromosome 15 can cause developmental delays, delayed growth and development, hypotonia, and characteristic facial features.

These changes include:  an extra copy of part of chromosome 15 in each cell, partial trisomy 15, or a missing segment of the chromosome in each cell, partial monosomy 15.

In some cases, several of the chromosome’s DNA building nucleotides are deleted or duplicated.

The following diseases are some of those related to genes on chromosome 15:

Bloom syndrome

Breast cancer

Isovaleric acidemia

Loeys–Dietz, type 3 (SMAD3 gene)

Marfan syndrome

Nonsyndromic deafness

Schaaf–Yang syndrome (SYS)

Tay–Sachs disease


Autosomal Dominant Compelling Helio-Ophthalmic Outburst syndrome[15]

Cytogenetic band


G-banding ideograms of human chromosome 15

G-banding ideogram of human chromosome 15 in resolution 850 bphs. Band length in this diagram is proportional to base-pair length. This type of ideogram is generally used in genome browsers (e.g. Ensembl, UCSC Genome

Leave a Reply

Your email address will not be published. Required fields are marked *