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HUWE1
HECT, UBA and WWE domain containing E3 ubiquitin protein ligase 1
HUWE1 encodes a large E3 ubiquitin ligase that regulates protein degradation and is essential for normal brain development and neuronal function. The HUWE1 gene provides instructions for making an enzyme that tags proteins for breakdown, controlling their levels within cells.
HUWE1 is located on the short (p) arm of chromosome X, at band Xp11.22. Arm ratio per GRCh38 - banding schematic.
Explore chromosome X in the library →Overview
HUWE1 (HECT, UBA and WWE domain containing E3 ubiquitin protein ligase 1) encodes one of the largest known E3 ubiquitin ligases in humans, a class of enzymes responsible for marking proteins for degradation through the ubiquitin-proteasome system. The gene is located on the X chromosome and plays critical roles in cellular quality control, DNA damage response, and developmental signalling pathways.
Pathogenic variants in HUWE1 cause an X-linked neurodevelopmental disorder characterised by intellectual disability, distinctive facial features, and in some cases, craniosynostosis (premature fusion of skull bones). Because the gene sits on the X chromosome, males with one pathogenic variant are typically more severely affected than females, who have a second copy of the gene on their other X chromosome that may partially compensate.
What the gene does
The HUWE1 protein functions as an E3 ubiquitin ligase, catalysing the attachment of ubiquitin molecules to target proteins within cells. This molecular tagging serves as a signal for the proteasome, a cellular machine that breaks down marked proteins into their component parts. By controlling which proteins are degraded and when, HUWE1 helps regulate essential processes including cell division, response to DNA damage, and programmed cell death.
This enzyme shows particular importance in the developing brain, where it regulates proteins involved in neuronal differentiation and migration. HUWE1 targets multiple substrates for degradation, including proteins that control cell cycle progression and apoptotic pathways. The protein's catalytic activity depends on its HECT domain, which directly transfers ubiquitin to substrate proteins, whilst other regions of the enzyme recognise and bind specific target proteins. Through these coordinated activities, HUWE1 maintains appropriate protein levels during critical developmental windows.
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Chromosome location
HUWE1 is located on the short arm of the X chromosome at position Xp11.22. The gene spans a substantial genomic region and contains multiple exons that are transcribed and spliced together to produce the mature messenger RNA. Its position on the X chromosome means that males inherit only one copy from their mothers, whilst females inherit one copy from each parent.
Protein structure
The HUWE1 protein comprises 4,374 amino acids, making it one of the largest E3 ubiquitin ligases characterised to date. The protein contains several functionally important domains distributed along its length. Near the middle of the sequence sits a UBA domain (approximately amino acids 1316-1355), which binds ubiquitin chains, followed by a UIM domain (approximately amino acids 1370-1389) that also recognises ubiquitin. A WWE domain (approximately amino acids 1603-1680) contributes to substrate recognition. Towards the C-terminal region, two UBM domains (approximately amino acids 2962-2995 and 3009-3044) provide additional ubiquitin-binding capacity. The protein also contains extensive disordered regions interspersed throughout its structure, which may provide flexibility for interactions with diverse substrate proteins. The catalytic HECT domain resides at the C-terminus (approximately amino acids 4000-4374), where it performs the actual transfer of ubiquitin molecules to target proteins.
Key variants
Pathogenic variants in HUWE1 typically result in loss of function, reducing the protein's ability to regulate its target substrates effectively. Most disease-causing variants are missense changes that disrupt protein structure or nonsense variants that truncate the protein prematurely. Because HUWE1 follows X-linked inheritance, males with a single pathogenic variant generally show more pronounced features than heterozygous females, though some carrier females may exhibit mild intellectual disability or learning difficulties.
Sample of pathogenic variants
10 pathogenic / likely-pathogenic variants from ClinVar, ranked by review status (expert-panel-reviewed first). This is a sample; recurrent founder variants in a specific population may not appear here - see the full ClinVar listing via the link above.
| Variant (HGVS) | Protein change | Classification | Evidence | Associated condition |
|---|---|---|---|---|
c.12037C>T | p.Arg4013Trp | Pathogenic/Likely pathogenic | ★★☆☆ | HUWE1-related disorder |
c.12691T>C | p.Tyr4231His | Pathogenic/Likely pathogenic | ★★☆☆ | Intellectual disability, X-linked syndromic, Turner type |
c.12928G>C | p.Gly4310Arg | Pathogenic/Likely pathogenic | ★★☆☆ | Intellectual disability, X-linked syndromic, Turner type |
c.329G>A | p.Arg110Gln | Pathogenic | ★★☆☆ | Inborn genetic diseases |
c.567+1G>C | - | Pathogenic | ★★☆☆ | Intellectual disability, X-linked syndromic, Turner type |
c.8942G>A | p.Arg2981His | Pathogenic/Likely pathogenic | ★★☆☆ | Intellectual disability, X-linked syndromic, Turner type |
c.9208C>T | p.Arg3070Cys | Pathogenic/Likely pathogenic | ★★☆☆ | HUWE1-related disorder |
c.9209G>A | p.Arg3070His | Pathogenic | ★★☆☆ | not provided |
c.12091T>C | p.Tyr4031His | Pathogenic | ★☆☆☆ | Intellectual disability, X-linked syndromic, Turner type |
c.2960del | p.Gly987fs | Pathogenic | ★☆☆☆ | Intellectual disability, X-linked syndromic, Turner type |
Evidence stars indicate ClinVar review status. Individual variant interpretation should always be performed by a qualified clinical laboratory - many variants remain classified as Variants of Uncertain Significance (VUS) pending more research.
Associated conditions
Pathogenic variants in HUWE1 cause a neurodevelopmental disorder characterised primarily by intellectual disability ranging from mild to severe. Affected individuals may present with delayed speech and motor development, distinctive facial features that may include a prominent forehead and deep-set eyes, and behavioural differences. Some individuals develop craniosynostosis, particularly affecting multiple skull sutures. Seizures occur in a subset of cases. The phenotypic spectrum varies considerably, with some males showing profound disability whilst others have milder learning difficulties and function relatively independently.
No disease links recorded for this gene in our reference set.
Inheritance pattern
Conditions caused by pathogenic HUWE1 variants typically follow x-linked inheritance.
X-linked recessive: sons of a carrier mother have a 50% chance of being affected. Daughters have a 50% chance of being carriers.
UK clinical status
Within the NHS Genomic Medicine Service, HUWE1 appears on multiple national testing panels reflecting its role in neurodevelopmental conditions. The gene holds green (diagnostic-grade evidence) status on the Intellectual Disability panel (R29) and the Fetal Anomalies panel (R21), indicating strong evidence for clinical use in these contexts. It is also listed with green status on the Rare Syndromic Craniosynostosis or Isolated Multisuture Synostosis panel (R100). Additionally, HUWE1 features in the Developmental Disorders Genotype-to-Phenotype (DDG2P) database with green classification, supporting its inclusion in diagnostic testing for unexplained developmental delay.
Sources: NHS GMS PanelApp · Genomics England PanelApp · NHS National Genomic Test Directory
Diet & lifestyle considerations
No specific lifestyle modifications have been shown to modify HUWE1-related outcomes. Management focuses on educational support, developmental therapies, and monitoring for associated medical features such as seizures or craniosynostosis.
Supplement considerations
No specific supplements have been shown to modify HUWE1-related outcomes. Any nutritional interventions should be guided by individual clinical needs rather than the genetic diagnosis itself.
Frequently asked questions
Why does HUWE1 predominantly affect males?
HUWE1 is located on the X chromosome, so males have only one copy whilst females have two. Males with a pathogenic variant lack a backup copy, typically resulting in more severe features, whereas many females with one pathogenic variant have milder or no symptoms due to their second, functional copy.
Can HUWE1 variants be inherited from parents?
Yes, pathogenic HUWE1 variants can be inherited from a carrier mother or arise as new (de novo) changes. Carrier mothers have a 50% chance of passing the variant to each child, with sons who inherit it typically more affected than daughters.
What does it mean that HUWE1 is an E3 ubiquitin ligase?
E3 ubiquitin ligases are enzymes that attach small ubiquitin proteins to other proteins as a tag, signalling them for breakdown by cellular machinery. HUWE1 controls the levels of multiple proteins involved in brain development and cellular quality control through this tagging process.