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PubMed This is a summary of 17 peer-reviewed journal articles Updated
Neurology

Imaging, Pathology, and Diagnosis of BSVD4

At a Glance

BSVD4 diagnosis combines brain MRI with genetic testing that can detect the COL4A1 AluYa5 insertion. MRI may show pontine lesions, white-matter changes, or microbleeds, while eye, kidney, and neurological exams help establish a baseline.

Diagnosing Brain Small Vessel Disease 4 (BSVD4) is a detective process that combines advanced brain imaging with specialized genetic testing. Because BSVD4 is rare, your medical team uses these tools to distinguish it from more common causes of small vessel disease, such as high blood pressure or aging [1].

Hallmark Findings on Brain MRI

The primary tool used to see the clinical effects of BSVD4 is an MRI (Magnetic Resonance Imaging). Doctors look for specific patterns in the brain that suggest the blood vessels are fragile [2]. The presence of these patterns supports the diagnosis, though their absence does not exclude it.

  • Pontine Lesions: In many patients with the AluYa5 insertion, the MRI shows multiple small, oval-shaped areas of damage in the pons (a critical part of the brainstem) [2][3]. These are small strokes (lacunar infarcts) that some doctors descriptively refer to as the “raisin bread sign,” though it is not a formal test [4].
  • White Matter Changes: You may see “diffuse white-matter disease” or leukoencephalopathy. This appears as bright spots on the MRI, indicating prior small-vessel injury [5][6].
  • Microbleeds: Because the vessel “scaffolding” is weak, the MRI may also show tiny spots of old bleeding, called cerebral microbleeds, or larger areas of bleeding (intracerebral hemorrhage) [7][8].

Molecular Confirmation

While an MRI and clinical phenotype establish clinical relevance, genetic testing is used to confirm the molecular variant. This is essential because BSVD4 can look very similar to other genetic conditions like CADASIL or CARASIL on a scan [1].

However, standard genetic tests sometimes miss the AluYa5 insertion [9]. Most standard panels are designed to find tiny “typos” in the DNA. The BSVD4 mutation is a mobile-element insertion (MEI)—a large chunk of extra DNA that has inserted itself into the 3′ untranslated region (3′UTR) of the COL4A1 gene [2].

  • Why tests miss it: Standard sequencing reads DNA in very short pieces. If the insertion is larger than those pieces, some short-read pipelines or targeted panels may fail to realize it is there [9][10].
  • The right test: To confirm BSVD4, you should ask the laboratory whether its method is validated to detect structural variants and the known Alu insertion [11][12]. A negative test may require review by a clinical geneticist, and any variant of uncertain significance requires careful interpretation.

Baseline Evaluation Checklist

Because COL4A1 mutations can affect several parts of the body, a baseline evaluation requires more than just a brain scan. While not every patient will have all these features, the following evaluations help guide surveillance [13]:

  1. Brain MRI (with SWI or T2 sequences):* This specialized MRI setting is better at finding the tiny microbleeds that are common in this condition [1].
  2. Specialized Genetic Testing: Ensure the test specifically looks for insertions and structural variants in the COL4A1 gene, not just simple point mutations [14].
  3. Comprehensive Eye Exam: An ophthalmologist should look at the back of the eye (the fundus) for retinal vascular tortuosity—twisted blood vessels that can be a feature of the condition, alongside cataracts or anterior-segment abnormalities [13][15].
  4. Kidney Function Screening: This includes a simple urine test (urinalysis) to check for microscopic blood or protein, and a blood test (eGFR) to ensure your kidneys are filtering correctly [16][17].
  5. Neurological Baseline: A thorough exam to document your current strength, balance, and memory to serve as a reference point for the future [5].

By completing this full assessment, you and your doctors can create a personalized plan to monitor your health and minimize future risks [13].

Common questions in this guide

What can a brain MRI show in BSVD4?
A brain MRI may show multiple small areas of damage in the pons, diffuse white-matter changes, and tiny old bleeds called cerebral microbleeds. Some people may also have a larger brain bleed. These findings can support BSVD4, but their absence does not rule it out.
Can routine genetic testing miss the BSVD4 mutation?
Yes. The AluYa5 change is a relatively large DNA insertion in the COL4A1 gene, and some short-read sequencing pipelines or targeted panels may miss this type of structural change. Ask whether the laboratory method is validated to detect the AluYa5 insertion and other structural variants.
What baseline tests are recommended for BSVD4?
Baseline evaluation commonly includes a brain MRI with SWI or T2* sequences, genetic testing that can detect COL4A1 insertions, a comprehensive eye exam, kidney tests such as urinalysis and eGFR, and a neurological examination. These results give your clinicians a reference for future monitoring.
How can doctors tell BSVD4 apart from CADASIL, CARASIL, or PADMAL?
These inherited small-vessel diseases can have overlapping MRI findings. Doctors compare your symptoms and family history with the MRI pattern and use genetic testing to identify the responsible variant, including a test that can detect the BSVD4 AluYa5 insertion. A clinical geneticist can help interpret a negative or uncertain result.
Can BSVD4 affect the eyes and kidneys?
Yes. COL4A1-related disease may be associated with retinal blood-vessel changes, cataracts, or other eye findings, as well as kidney abnormalities such as blood or protein in the urine. An ophthalmology exam, urinalysis, and eGFR can help establish a baseline.

Questions For You

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Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Does my genetic test specifically use tools (like MEI or structural variant callers) capable of finding the AluYa5 insertion in the 3'UTR, rather than just standard sequencing?
  2. 2.What is my 'baseline' MRI showing today, and are there signs of pontine lesions?
  3. 3.How frequently should I have my eyes and kidneys screened based on my specific genetic result?
  4. 4.Can you explain the difference between my result and other conditions like CADASIL or PADMAL?

References

References (17)
  1. 1

    Monogenic causes of cerebral small vessel disease and stroke.

    Guey S, Chabriat H

    Handbook of clinical neurology 2024; (204()):273-287 doi:10.1016/B978-0-323-99209-1.00018-1.

    PMID: 39322384
  2. 2

    An AluYa5 Insertion in the 3'UTR of COL4A1 and Cerebral Small Vessel Disease.

    Aloui C, Neumann L, Bergametti F, et al.

    JAMA network open 2024; (7(4)):e247034 doi:10.1001/jamanetworkopen.2024.7034.

    PMID: 38630472
  3. 3

    Disruption of a miR-29 binding site leading to COL4A1 upregulation causes pontine autosomal dominant microangiopathy with leukoencephalopathy.

    Verdura E, Hervé D, Bergametti F, et al.

    Annals of neurology 2016; (80(5)):741-753 doi:10.1002/ana.24782.

    PMID: 27666438
  4. 4

    'Raisin bread sign' feature of pontine autosomal dominant microangiopathy and leukoencephalopathy.

    Kikumoto M, Kurashige T, Ohshita T, et al.

    Brain communications 2023; (5(6)):fcad281 doi:10.1093/braincomms/fcad281.

    PMID: 37953842
  5. 5

    Pontine autosomal dominant microangiopathy with leukoencephalopathy in a Hispanic man without a family history.

    Shah A, Hussain U, Ekpruke C, et al.

    Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association 2026; (35(9)):108700 doi:10.1016/j.jstrokecerebrovasdis.2026.108700.

    PMID: 42437605
  6. 6

    Stratification of Phenotypes in Childhood-Onset COL4A1/COL4A2-Related Disorders Based on Age of Presentation.

    Porcari GS, Rashid RN, Mulvihill CA, et al.

    Neurology. Genetics 2026; (12(3)):e200386 doi:10.1212/NXG.0000000000200386.

    PMID: 42099677
  7. 7

    Main features of COL4A1-COL4A2 related cerebral microangiopathies.

    Guey S, Hervé D

    Cerebral circulation - cognition and behavior 2022; (3()):100140 doi:10.1016/j.cccb.2022.100140.

    PMID: 36324412
  8. 8

    A Novel Mutation in COL4A1 Gene in a Chinese Family with Pontine Autosomal Dominant Microangiopathy and Leukoencephalopathy.

    Li Q, Wang C, Li W, et al.

    Translational stroke research 2022; (13(2)):238-244 doi:10.1007/s12975-021-00926-0.

    PMID: 34415564
  9. 9

    In Silico identification of a common mobile element insertion in exon 4 of RP1.

    Won D, Hwang JY, Shim Y, et al.

    Scientific reports 2021; (11(1)):13381 doi:10.1038/s41598-021-92834-4.

    PMID: 34183725
  10. 10

    Assessing the utility of long-read nanopore sequencing for rapid and efficient characterization of mobile element insertions.

    Watson CM, Crinnion LA, Lindsay H, et al.

    Laboratory investigation; a journal of technical methods and pathology 2021; (101(4)):442-449.

    PMID: 32989232
  11. 11

    Mobile element insertions in rare diseases: a comparative benchmark and reanalysis of 60,000 exome samples.

    Wijngaard R, Demidov G, O'Gorman L, et al.

    European journal of human genetics : EJHG 2024; (32(2)):200-208 doi:10.1038/s41431-023-01478-7.

    PMID: 37853102
  12. 12

    Long-read sequencing improves the genetic diagnosis of retinitis pigmentosa by identifying an Alu retrotransposon insertion in the EYS gene.

    Fernández-Suárez E, González-Del Pozo M, Méndez-Vidal C, et al.

    Mobile DNA 2024; (15(1)):9 doi:10.1186/s13100-024-00320-1.

    PMID: 38704576
  13. 13

    Multiorgan manifestations of COL4A1 and COL4A2 variants and proposal for a clinical management protocol.

    Gasparini S, Balestrini S, Saccaro LF, et al.

    American journal of medical genetics. Part C, Seminars in medical genetics 2024; (196(4)):e32099 doi:10.1002/ajmg.c.32099.

    PMID: 39016117
  14. 14

    Limitations of short-read NGS in detecting RP1 Alu insertions: a case emphasizing Sanger confirmation.

    Hayashi T, Mizobuchi K, Higa N, et al.

    Ophthalmic genetics 2026; (47(2)):204-208 doi:10.1080/13816810.2025.2590162.

    PMID: 41290015
  15. 15

    Venous Tortuosity in COL4A2-Associated Gould Syndrome.

    Oh JK, Levi SR, de Carvalho JRL, et al.

    Ophthalmic surgery, lasers & imaging retina 2023; (54(9)):536-539 doi:10.3928/23258160-20230811-01.

    PMID: 37642429
  16. 16

    Hereditary cerebral small vessel disease and stroke.

    Søndergaard CB, Nielsen JE, Hansen CK, Christensen H

    Clinical neurology and neurosurgery 2017; (155()):45-57 doi:10.1016/j.clineuro.2017.02.015.

    PMID: 28254515
  17. 17

    HANAC Syndrome Col4a1 Mutation Causes Neonate Glomerular Hyperpermeability and Adult Glomerulocystic Kidney Disease.

    Chen Z, Migeon T, Verpont MC, et al.

    Journal of the American Society of Nephrology : JASN 2016; (27(4)):1042-54 doi:10.1681/ASN.2014121217.

    PMID: 26260163

This page is for informational purposes only and does not constitute medical advice. Your neurologist, clinical geneticist, and other specialists should interpret your MRI and genetic results and recommend appropriate surveillance.