Private Fragile X Syndrome screen - FMR1 repeat analysis PCR London
Fragile X Syndrome screen - FMR1 repeat analysis PCR is a private test offered at our clinic in Marylebone, London. It should be ordered and interpreted by a registered clinician based on your symptoms and clinical context.
Fragile X Syndrome screen - FMR1 repeat analysis PCR
Test fee £620 + £50 phlebotomy fee (per visit)
- Results in 5 weeks"
- UKAS accredited laboratory
- Professional phlebotomy service
- Confidential results portal
Or call 020 7183 0692
Pay at clinic on the day of your appointment
Fragile X Syndrome Screen – FMR1 Repeat Analysis in London
Fragile X Syndrome FMR1 repeat analysis is available at Wimpole Street Medical and Dental, our clinic in Marylebone, London W1G. This test is priced at £620. A £50 phlebotomy fee applies per visit for blood collection. It requires a venous blood sample, and results are typically available within 5 weeks. A referral from a clinical geneticist is required before this test can be ordered.
Fragile X Syndrome is the most common inherited cause of intellectual disability and the most common single-gene cause of autism spectrum disorder. It is caused by an expansion of CGG trinucleotide repeats in the FMR1 gene on the X chromosome. This PCR-based test measures the number of CGG repeats to determine carrier status or affected status.
Who Should Consider Fragile X FMR1 Testing?
Children with developmental delay, intellectual disability, or autism spectrum features, particularly boys. Women with premature ovarian insufficiency (menopause before age 40) or a family history of Fragile X. Men over 50 with progressive tremor and ataxia (Fragile X-associated tremor/ataxia syndrome, FXTAS). Individuals with a family history of intellectual disability or Fragile X.
Normal alleles have 5-44 CGG repeats. Intermediate alleles (45-54 repeats) may be unstable but do not cause Fragile X. Premutation alleles (55-200 repeats) can cause FXTAS in older men and premature ovarian insufficiency in women. Full mutations (over 200 repeats) cause Fragile X Syndrome. Female carriers have a 50% chance of passing the expansion to each child.
A trained nurse collects the blood sample by standard venepuncture at our clinic on Wimpole Street, a short walk from Bond Street and Oxford Circus stations. A referral from a clinical geneticist is required, please call 020 7183 0692 to arrange.
Genetic Investigation
Fragile X Syndrome screen - FMR1 repeat analysis PCR provides genetic information that should be ordered alongside appropriate genetic counselling and clinical assessment.
- Family history of the condition
- Personal symptoms suggestive of the condition
- Confirmation of a clinical diagnosis
- Carrier or reproductive risk assessment
- Specialist clinical genetics workup
- Clinician-directed testing
Your Appointment, Step by Step
Reserve Online
Pick a date and time that fits your diary
Come to Marylebone
22 Wimpole Street, near Bond Street & Oxford Circus
Sample Taken by a Nurse
A brief, gentle blood draw, around 5 minutes
Report Delivered Securely
Results in 5 weeks"
Frequently Asked Questions
What patients most often want to know before this test
Find Us in Marylebone
In the heart of London's Harley Street medical district, moments from Oxford Street
Address
Wimpole Street Medical & Dental
22 Wimpole Street
Marylebone
London W1G 8GQ
Getting Here
- Short walk from Bond Street station (Elizabeth, Central & Jubilee lines)
- Oxford Circus (Victoria, Central & Bakerloo lines) also nearby
Opening Hours (from 1 October 2026)
- Monday, Wednesday9am - 6pm
- Tuesday, Thursday9am - 8pm
- Friday8am - 5pm
- Saturday10am - 4pm
- SundayClosed
Contact
Arrange Your Test in Marylebone
You won't need a GP referral, simply reserve a slot online and visit us at 22 Wimpole Street. Your report follows within 5 weeks".
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Meet Our Medical Team
Our experienced medical team is fully qualified and registered with the GMC and NMC, delivering safe, high-quality care in line with the highest professional standards.
Because our patients deserve nothing less.
Registered. Regulated. Trusted.
At Wimpole Street Medical & Dental, our clinicians are registered with the relevant UK regulatory bodies, including the GDC, GMC and NMC. Our dentists, dental nurses and medical professionals deliver care that meets the highest clinical, safety and ethical standards, because our patients deserve nothing less.
We Accept All Major Dental Insurances
We accept all major UK dental insurances, including AXA PPP Healthcare Dental Cover, Aviva Dental Insurance, Bupa Dental Cover, Cigna Dental Insurance, Vitality Dental Health Insurance, Unum and Boots Dental Plan Cover. We provide itemised receipts so you can claim back your treatment costs.
