The North West Thames Regional Genetics Service offers genetic counselling and genetic diagnosis to individuals and families living in north west London, parts of Hertfordshire and Bedfordshire.

Telephone: 020 8869 2795
Location: North West Thames Regional Genetics Service, Level 8V, St. Mark's Hospital
Division: Integrated clinical service

About the service

The North West Thames Regional Genetics Service offers genetic counselling and genetic diagnosis to individuals and families living in the area.

We are likely to be your regional genetics centre if your GP surgery is located in:

  • Bedfordshire
  • Brent
  • Chelsea
  • Ealing
  • Edgware
  • Hammersmith
  • Harrow
  • Hertfordshire
  • Hillingdon
  • Hounslow
  • Kensington
  • Westminster.

We are based at Northwick Park and St Mark's Hospitals, but we also offer outreach clinics in different hospitals across the region.

If you are concerned about your health, the health of a family member, or your family history, you should first speak to your family doctor or GP. They may be able to answer your question, or they may refer you on to our service or another service that can help. 

If you are referred to our service, you will receive an appointment at one of our clinics.

Other services we provide

Where we provide your care

We hold clinics at several different hospitals across the region. Your appointment letter will state where the clinic will be held. You may need to travel further if attending a specialist clinic.

If you live outside of the North West Thames area, you can find your local genetics service on the Genetic Alliance org website.

Barnet Hospital

  • Address: Wellhouse Lane, Barnet, Herts, EN5 3DJ
  • Telephone: 020 8216 4600 or 0845 111 4000
  • Genetics clinics:
    • Main outpatients (clinic 1, 2 or 3) on level one of the main building.
    • Children’s outpatients on level two of the main building

Bedford (Child Development Centre)

  • Address: Child Development Centre (CDC), Hill Rise, Kempton, MK42 7EB
  • Telephone: 01234 310278

Bedford Hospital

  • Address: Bedford Hospital, Kempston Road, Bedford, MK42 9DJ
  • Telephone: 01234 355122
  • Genetic clinics:
    • Paediatric outpatient department at the South Wing, Bedford Hospital.
    • Outpatient department, Breast Clinic

Charing Cross Hospital

  • Address: Fulham Palace Road, London, W6 8RF
  • Telephone: 020 3311 1234
  • Genetics clinics: main outpatients department, first floor, clinic block

Chelsea and Westminster Hospital

  • Address: 369 Fulham Road, London, SW10 9NH
  • Telephone: 020 8746 8000
  • Genetics clinics: paediatric outpatient department, ground floor

Ealing Hospital

  • Address: Ealing Hospital, Uxbridge Road, Southall Middlesex, UB1 3HW
  • Telephone: 0208 967 5000
  • Genetics clinics:
    • The main outpatients department
    • The antenatal department in the maternity wing

Hammersmith Hospital  and  Queen Charlotte's & Chelsea Hospital

  • Address: Du Cane Road, London, W12 0HS
  • Telephone:
    • Queen Charlotte’s Hospital: 020 3313 1111
    • Hammersmith Hospital : 020 3313 1000
  • Genetics clinics are held in the following locations:
    • The Centre for Fetal Care, second floor, Queen Charlotte’s Hospital
    • Paediatric outpatients, ground floor, D Block, Northside, Hammersmith Hospital
    • Cancer clinic, gynaecology outpatients, ground floor, Queen Charlotte’s Hospital
    • Main outpatient clinic in Hammersmith Hospital

Heart of Hounslow Polyclinic

  • Address: Heart of Hounslow, 92 Bath Road, Hounslow, Middlesex, TW3 3LN
  • Telephone: 020 8630 1425
  • Genetics clinics: Children’s Services, ground floor

Hemel Hempstead Hospital

  • Address: Hillfield Road, Hemel Hempstead, Herts, HP2 4AD
  • Telephone: 01442 213 141
  • Genetics clinics: antenatal clinic, maternity unit, level 2, Verulam wing

Hertford County Hospital

  • Address: Hertford County Hospital, North Road, Hertford, Herts, SG14 1LP
  • Telephone: 01707 328111
  • Genetics clinics: clinic A.  

Hillingdon Hospital

  • Address: Hillingdon Hospital, Pield Health Road, Uxbridge, UB8 3NN
  • Telephone: 01895 238282
  • Genetics clinics:
    • Paediatric Outpatient department, lower ground floor (Peter Pan and Wendy Wards)
    • Cumberlege Centre, third floor, main tower block

Lister Hospital

  • Address: Coreys Mill Lane, Stevenage, Hertfordshire, SG1 4AB
  • Telephone: 01438 314333
  • Genetic clinics:
    • Main outpatients, clinic F
    • Forster Suite, Level 10, Tower block

Luton and Dunstable Hospital

  • Address: Luton and Dunstable University Hospital, Lewsey Road, Luton LU4 0DZ
  • Telephone: 01582 49 11 66 
  • Genetics clinics: main outpatients and children’s outpatients, main hospital building.

Northwick Park Hospital (Kennedy Galton Centre)

  • Address: Northwick Park Hospital and St Mark’s Hospital, Watford Road, Harrow. HA1 3UJ
  • Telephone: 020 8864 3232
  • Genetics clinics are held in the following locations:
    • Kennedy Galton Centre, level 8, St Mark’s Hospital
    • Northwick Park: main outpatients
    • Chaucer Unit, level three, paediatric department

St Albans City Hospital

  • Address: Waverley Road, St Albans, Herts, AL3 5PN
  • Telephone: 01727 866 122
  • Genetics clinics: Breast Care Unit, ground floor, main building

St Mary’s Hospital

  • Address: Praed Street, London W2 1NY
  • Telephone: 020 3312 6666
  • Genetics clinics: paediatric outpatients, 6th floor, Queen Elizabeth the Queen Mother Building

Watford General Hospital

  • Address: Vicarage Road, Watford, Herts, WD18 0HB
  • Telephone: 01923 244 366 
  • Genetics clinics:
    • Fracture clinic
    • Children’s outpatients

West Middlesex Hospital

  • Address: Twickenham Road, Isleworth, Middlesex TW7 6AF
  • Telephone: 020 8560 2121  
  • Genetics clinics:
    • children’s outpatients, third floor, East Wing, main building

Joint colorectal cancer genetics clinics, outpatients department 4, ground floor, East Wing, main building

Screening options for Jewish genetic disorders

If you have one or more grandparents of Jewish descent, you have two screening options:

Tay-Sachs carrier screening only

If you live in north west London, your GP can send an electronic referral (eRS) to our genetics service for a virtual or in-person appointment. If you or your partner are pregnant, the gestational age must be included in the referral. A genetic counsellor will then discuss and arrange your free Tay-Sachs disease carrier screening using a blood sample.  

Screening for Tay-Sachs disease and other Jewish genetic disorders

If you'd like to be tested for 47 recessively inherited genetic conditions (including Tay-Sachs disease, see information about the condition on the website), that are relevant to Jewish communities, visit website for information on available tests

How to make a referral to genetics

To make a referral:

Urgent referrals should be clearly marked as urgent and referrals must include your patient's:

  • full name
  • address
  • date of birth
  • NHS number
  • GP details
  • reason for being referred to the genetics clinic.

Please include as much information as possible about the specific condition or suspected condition in the family. Sometimes another family member of your patient might have a confirmed genetic diagnosis. If this is the case, please include the following wherever possible:

  • a specific diagnosis 
  • relevant test reports
  • the exact biological relationship between the affected individual and the person being referred eg half-sister (same mother).

Genetics excluded conditions for referral

  • Alpha 1 antitrypsin deficiency: genetic testing can be arranged at the local hospital laboratory
  • carrier testing: read the Autosomal recessive inheritance and carrier testing letter for patients [docx] 1MB for more information
  • Ehlers Danlos Syndrome (EDS) or Hypermobility Spectrum Disorder (HSD): suspected rare types of EDS can be referred to the Ehlers-Danlos Syndrome (EDS) national diagnostic service at Northwick Park Hospital
  • familial hypercholesterolaemia: refer patient to the local lipid clinic
  • G6PD: refer patient to Sickle cell and thalassaemia centre at Central Middlesex Hospital
  • haemochromatosis: a genetic test can be arranged using the molecular, cytogenetic, neurogenetic and NIPD test request form
  • haemoglobinopathies: we will accept referral if there are known disease causing gene variants and the couple want to consider pre-implantation genetic diagnosis (PGD), otherwise please refer to the Sickle Cell and Thalassaemia Centre at Central Middlesex Hospital  
  • haemophilia: refer patient to the local haemophilia unit
  • infertility: investigations can be carried by the GP or fertility specialist and refer to us if any abnormalities are found in the genetic investigations
  • isolated arrhythmia/cardiomyopathy: genetic testing can be arranged by the patient's specialist doctor. We accept referrals to see the patient with their gene test result if further explanation is required, or the patient wishes to discuss the implications of the result for themselves, other family members or their children. We can arrange cascade screening of other family members if appropriate.
  • isolated autism: we use the recommended Autism flow chart [pptx] 76KB. We no longer accept referrals for children with autism unless they also have:
    • significant dysmorphic features
    • otherwise unexplained developmental delay
    • consanguinity
    • one or more affected siblings
    • microcephaly or macrocephaly (>2 SD from mean)
    • epilepsy
    • neurocutaneous abnormalities
    • a significant abnormality reported on array CGH or other genetic testing
  • MTHFR: we do not offer MTHFR testing as it is not indicated in screening for thrombophilia
  • recurrent miscarriages: baseline investigations for couples with recurrent miscarriages are carried out by the obstetrics team. We can accept referrals if an abnormality is identified on the chromosomal/genetic investigations
  • thrombophilia: refer patient to the local thrombophilia clinic

We may reject the following referrals if the patient is undergoing further genetic tests or medical assessments:

  •  Microarray (detailed chromosome examination): 
    • patients presenting with intellectual deficit, developmental delay, with or without dysmorphism or multiple (more than 3) congenital abnormalities will usually be eligible to have a microarray as a first line investigation
    • if a non-urgent referral is made for genetic investigations for a patient with one or more of the medical problems above, the referral may be rejected pending a discussion about the option of a microarray and the organisation of a microarray by the referring clinician. Complete the blood form to request a microarray test for the genomics laboratory  at Cambridge University Hospitals. The microarray information letter for parents [doc] 129KB can be printed and given to patients. Once a microarray is in process, the referral can be accepted. A genetic referral can still be made should the family decline the option of a microarray following discussion with the referring clinician.
    • In urgent cases, such as new-born infants with a suspected chromosome syndrome, prenatal cases or acutely unwell patients, the referral will be accepted with or without a microarray.
  • Possible Marfan syndrome: we will see patients where the possibility of Marfan syndrome or a related connective tissue disorder has been raised. We will take the family and personal history and will examine for systemic features of Marfan syndrome. We will consider other overlapping conditions, and it would be helpful for the patient to have a completed echocardiogram and ophthalmology reviews to rule out any concerns with the eyes. If the patient or a member of the patient’s family has been seen at the Royal Brompton & Harefield Hospital, we can arrange for the patient to be seen at their Connective Tissue Disorders/Aortopathy clinic if required.

Referrals for women who are pregnant

If you are referring a woman who is pregnant, please:

Cancer genetic referral

If your patient meets our cancer genetic referral criteria:

We will review the referral and may request more information from the patient by asking them to complete the patient family history questionnaire

After assessing the full information we will either offer your patient an appointment or send them a letter containing appropriate screening advice.

Please let your patient know that it's important for us to confirm the family history, where possible, in order to determine eligibility. Unfortunately, this can cause delay especially if we don't have enough information at the beginning of the process.

If your patient or their family member has an identified genetic cancer susceptibility gene, we will accept a referral. We will need a copy of the genetic test report from the family member who has been tested.

If your patient's family does not have an identified genetic cancer susceptibility gene, then we usually only offer an appointment to someone who is affected. In some cases, where there is no affected relative available for testing, we would consider assessing an unaffected individual. The affected relatives must be blood relations, but can be through the maternal or the paternal side.

Please include any histology reports, such as receptor status or mismatch repair immunohistochemistry reports when completing the electronic referral. 

For more advice on a referral relating to cancer, please contact us:

Rapid genetic testing for breast or ovarian cancer

We offer expedited testing of high-risk breast and ovarian cancer associated genes, including BRCA1, BRCA2 and PALB2 for patients who:

  • meet the testing criteria
  • where expedited results would influence cancer management

To request expedited testing please complete the BRCA urgent referral form and email this to the genetics referral team

Laboratory services for genetics

Our laboratory services are provided by North East Thames Regional Genetics Services, based at Great Ormond Street Hospital. You can contact them:

More information about genetics

Information about genetics

  • Genetic Alliance UK: the national charity of over 130 patient organisations, supporting all those affected by genetic conditions. The website contains an introduction to genetics and genetic conditions and has many patient information leaflets.
  • Unique Rare Chomosome Disorder Support Group provides information and support to families and individuals affected by any rare chromosome disorder.
  • Contact a Family provides support, advice and information for families with disabled children, no matter what their condition or disability.
  • Antenatal Results and Choices (ARC) is a national charity which provides non-directive support and information to parents throughout the antenatal testing process.

Information if you're coming to our service because you have a family history of cancer

  • Macmillan provide practical, medical and financial support and push for better cancer care. 
  • Breast Cancer Now offers support and information to people affected by breast cancer. Specific information is available for people with a family history of breast cancer.
  • Bowel Cancer UK raises awareness and provides support and information to anybody worried about or affected by bowel cancer.

Genomics resources for healthcare professionals

The information on this page will assist health professionals in accessing the appropriate genetics resources needed for day-to-day patient care.

Genomic medicine can help improve diagnosis and care of patients and their families, and is relevant for all specialties. It is therefore important clinicians in all specialties to have access to training courses and have links with their regional genetics service.

Eligibility criteria for genetic testing

The NHS national genomic test directory can be found on the NHS England website This lists the eligibility criteria for all nationally commissioned genetic tests.

Laboratory links and test request forms

Genetic samples from most hospitals in the region are sent to the North Thames Genomic laboratory hub at Great Ormond Street Hospital, where test request forms for the genomic laboratory hub are also available.

Genetic samples from Lister, Hertford County, Luton and Bedford Hospitals are sent to the Cambridge genomic lab where request forms on the East Genomics website are available.

Education resources

We appreciate each specialty and department has different needs and we are able to provide tailored education sessions. Please email the genetics team to discuss your needs and make arrangements.