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Chromosome 10
Home of the PTEN tumour-suppressor (Cowden syndrome) and RET (MEN 2).
Schematic of chromosome 10 showing the short (p) and long (q) arms. Arm ratio per GRCh38 - banding schematic.
Available at Jeen Health
Clinical tests that include this
Overview
Chromosome 10 comprises roughly 4.3 per cent of the total human genome, containing approximately 735 protein-coding genes distributed across its 133.8 megabases. It is classified as a submetacentric chromosome, meaning the centromere sits off-centre, creating a shorter p arm and a longer q arm when viewed under the microscope during cell division. Clinically, chromosome 10 is recognised for carrying several important genes involved in tumour suppression and cellular signalling.
This chromosome has attracted considerable attention in cancer genetics and developmental biology. The long arm hosts PTEN, one of the most frequently altered tumour-suppressor genes across human cancers, and RET, a proto-oncogene whose pathogenic variants drive hereditary thyroid and endocrine tumours. The relatively high density of clinically significant genes on chromosome 10 means that testing panels for familial cancer syndromes and developmental disorders frequently include analysis of genes on this chromosome.
Structure
Chromosome 10's submetacentric architecture produces distinct short (p) and long (q) arms separated by the centromere, which attaches to spindle fibres during mitosis and meiosis. When cells prepare to divide, chromosome 10 condenses from loosely organised chromatin into the compact X-shaped structure visible under microscopy, with the centromere forming the constriction point. The q arm is substantially longer than the p arm, reflecting the off-centre position of the centromere.
At the molecular level, the DNA of chromosome 10 wraps around histone proteins to form nucleosomes, which coil into higher-order chromatin fibres. This packaging allows over 133 million base pairs to fit inside the nucleus whilst remaining accessible to the cellular machinery that reads genes and repairs DNA. Different regions of the chromosome adopt open or closed chromatin states depending on whether the genes they contain need to be active in a given cell type, with tightly packed heterochromatin typically silencing gene expression and loosely packed euchromatin permitting transcription.
Video: What is a karyotype?
Notable regions
The 10q23.31 band is among the most clinically significant regions of the chromosome, housing the PTEN gene. This tumour-suppressor encodes a phosphatase enzyme that acts as a brake on cell proliferation by counteracting growth signals. Constitutional pathogenic variants in PTEN cause Cowden syndrome, a hereditary cancer predisposition disorder characterised by hamartomatous overgrowths and elevated risks of breast, thyroid, endometrial, and other cancers. The same band also contains BMPR1A, which when altered can lead to juvenile polyposis syndrome, a condition featuring multiple gastrointestinal polyps and increased colorectal cancer risk. The clustering of two major tumour-suppressor genes in this region underscores its importance in growth regulation.
Further towards the centromere, the 10q11.21 band carries RET, a receptor tyrosine kinase essential for the development of nerve cells and kidneys. Gain-of-function pathogenic variants in RET drive multiple endocrine neoplasia type 2, a hereditary syndrome in which affected individuals develop medullary thyroid carcinoma, phaeochromocytoma, and parathyroid tumours. Loss-of-function variants in the same gene, by contrast, cause Hirschsprung disease, a congenital disorder of the intestinal nerve plexus. This dual role illustrates how the functional consequences of a variant depend critically on whether it increases or decreases the protein's activity.
On the short arm, the 10p14 band contains GATA3, a transcription factor crucial for kidney and inner-ear development as well as parathyroid gland formation. Pathogenic variants in GATA3 result in HDR syndrome (hypoparathyroidism, sensorineural deafness, and renal dysplasia), a rare multisystem developmental disorder. The 10p12.1 band houses WAC, encoding an adaptor protein involved in gene regulation; variants in WAC are associated with a neurodevelopmental syndrome featuring intellectual disability and behavioural features.
Notable genes
PTEN stands out as one of the most intensively studied tumour-suppressor genes in human genetics. By removing phosphate groups from signalling molecules in the PI3K-AKT pathway, PTEN prevents unchecked cell division and survival. Beyond its role in Cowden syndrome, somatic loss of PTEN function is observed across a wide spectrum of sporadic cancers, making it a key target in oncology research. Individuals with constitutional PTEN pathogenic variants require tailored cancer surveillance protocols coordinated through NHS clinical genetics and oncology services.
RET exemplifies how a single gene can contribute to multiple distinct clinical phenotypes depending on the nature of the variant. Activating pathogenic variants trigger the uncontrolled signalling that drives tumour formation in multiple endocrine neoplasia type 2, whilst inactivating changes impair the development of the enteric nervous system in Hirschsprung disease. Predictive genetic testing for RET pathogenic variants enables early intervention, including prophylactic thyroidectomy in childhood for some multiple endocrine neoplasia type 2 subtypes, highlighting the gene's importance in precision medicine. GATA3, BMPR1A, and ACTA2 similarly contribute to the chromosome's clinical portfolio, with ACTA2 variants causing familial thoracic aortic aneurysm through disruption of smooth muscle contraction in the aortic wall.
Chromosomal disorders
Unlike some chromosomes where whole-chromosome trisomy or monosomy produces well-recognised clinical syndromes, complete aneuploidy (abnormal number of chromosomes) involving chromosome 10 is generally incompatible with survival to term, with extremely rare exceptions reported in the medical literature. Mosaic trisomy 10, in which only a subset of cells carry an extra copy, has been reported in rare cases, typically presenting with developmental delay, growth restriction, and congenital anomalies, though the clinical picture is highly variable and the condition remains poorly characterised compared to the common autosomal trisomies.
Partial deletions and duplications involving segments of chromosome 10 are detected through chromosomal microarray analysis and can produce a range of developmental and congenital outcomes depending on the size and gene content of the affected region. Deletions encompassing the 10p14 region that remove GATA3 contribute to the renal and auditory features seen in some individuals, whilst larger terminal deletions may affect multiple genes and produce more complex phenotypes. Ring chromosome 10, a rare structural rearrangement in which the chromosome forms a circular structure after losing material from both ends, has been described in individuals with intellectual disability and dysmorphic features, though the severity depends on how much genetic material is lost during ring formation. These structural abnormalities are typically de novo events, arising spontaneously during parental germ-cell formation or early embryonic development.
Prenatal screening & diagnosis
Chromosome 10 abnormalities are not included in standard antenatal screening protocols such as non-invasive prenatal testing, which focuses on the common autosomal trisomies (13, 18, 21) and sex-chromosome aneuploidies. However, structural rearrangements involving chromosome 10 may be identified incidentally during karyotyping or chromosomal microarray analysis performed for other indications, such as advanced maternal age, abnormal ultrasound findings, or a family history of chromosome rearrangements.
When antenatal ultrasound reveals findings suggestive of a syndromic condition potentially linked to chromosome 10, such as renal anomalies or cardiac defects, invasive testing with chorionic villus sampling or amniocentesis may be offered to obtain foetal cells for chromosomal microarray or, if a specific gene is suspected based on family history, targeted sequencing, or depending on the clinical scenario and local pathways, rapid exome or genome sequencing. For families with a known pathogenic variant in a chromosome 10 gene such as RET or PTEN, preimplantation genetic testing or prenatal diagnosis can be discussed as part of reproductive genetic counselling through NHS genomic medicine services.
Inheritance & recurrence
Most clinically significant abnormalities involving chromosome 10 genes follow autosomal dominant inheritance, meaning a single pathogenic variant is sufficient to cause disease. Conditions such as Cowden syndrome, multiple endocrine neoplasia type 2, and familial thoracic aortic aneurysm due to ACTA2 variants typically show vertical transmission through families, though de novo variants account for a proportion of cases in each condition. When a parent carries a pathogenic variant, each child has a 50 per cent chance of inheriting it, though expressivity and penetrance vary by gene and specific variant.
Structural chromosome 10 abnormalities, such as deletions, duplications, or ring chromosomes, are usually de novo and carry a low recurrence risk in future pregnancies, typically quoted at around 1 per cent to account for the possibility of parental germline mosaicism. If a parent is found to carry a balanced translocation involving chromosome 10, the recurrence risk for unbalanced offspring is higher and depends on the specific breakpoints and segregation patterns, necessitating referral to clinical genetics for detailed risk assessment and discussion of reproductive options. Families affected by chromosome 10 conditions are encouraged to access NHS clinical genetics services for personalised counselling, cascade testing of at-risk relatives where appropriate, and coordination of surveillance or preventive interventions.
Frequently asked questions
What conditions are associated with chromosome 10?
Chromosome 10 harbours genes linked to several hereditary cancer syndromes and developmental disorders. Cowden syndrome and familial medullary thyroid carcinoma arise from pathogenic variants in PTEN and RET respectively, whilst ACTA2 variants cause familial thoracic aortic aneurysm and BMPR1A changes underlie juvenile polyposis syndrome. Structural abnormalities such as deletions or duplications of chromosome 10 segments can produce developmental delay and congenital anomalies, though whole-chromosome aneuploidy is rarely compatible with survival.
How is chromosome 10 tested in clinical genetics?
Testing depends on the clinical question. For individuals with a family history of Cowden syndrome or multiple endocrine neoplasia type 2, targeted gene sequencing of PTEN or RET is performed. Chromosomal microarray can detect deletions and duplications across chromosome 10, whilst karyotyping identifies large structural rearrangements such as translocations or ring chromosomes. These tests are accessed through NHS clinical genetics services following referral by a GP or specialist.
Can chromosome 10 abnormalities be inherited?
Pathogenic variants in chromosome 10 genes often follow autosomal dominant inheritance, with a 50 per cent chance of being passed from an affected parent to each child. However, many cases arise de novo, meaning the variant occurred spontaneously and was not inherited from either parent. Structural abnormalities such as deletions or ring chromosomes are usually de novo, carrying a low recurrence risk in future pregnancies unless a parent carries a balanced rearrangement.
What is the role of PTEN on chromosome 10?
PTEN encodes a phosphatase enzyme that regulates cell growth by opposing signals that drive proliferation and survival. Constitutional pathogenic variants in PTEN cause Cowden syndrome, a hereditary condition associated with hamartomas and elevated risks of breast, thyroid, endometrial, and other cancers. Somatic loss of PTEN function is also common in sporadic tumours. Individuals with pathogenic PTEN variants typically require enhanced cancer surveillance coordinated through clinical genetics and oncology.
Why does chromosome 10 matter in cancer genetics?
Chromosome 10 carries multiple genes central to cancer predisposition and tumour biology. PTEN is one of the most frequently altered tumour-suppressor genes across human cancers, whilst RET pathogenic variants drive hereditary thyroid and endocrine tumours. Understanding which chromosome 10 genes are involved helps guide surveillance protocols, surgical decisions, and in some cases targeted therapies. NHS genomic medicine increasingly incorporates chromosome 10 gene testing into cancer risk assessment and personalised treatment planning.
Launch-set genes on chromosome 10
Genes on this chromosome that currently have dedicated pages in the library. This list grows as we publish more.