Exclusive: NHS FOI Data Reveals Millions Spent Treating Patients with Recorded Family History of Cousin Marriage

Over the past five years, one NHS Trust alone has spent more than £3.6 million treating patients with a coded family history of consanguinity.

These findings, obtained through targeted FOI requests to University Hospitals Birmingham NHS Foundation Trust and Bradford Teaching Hospitals NHS Foundation Trust, reveal both a notable cost to public health services and a concerning lack of internal review around a sensitive but urgent public health issue.

This investigation began with a focused question: “What is the real-world cost of treating genetic disorders associated with cousin marriage?”

Cousin marriage, particularly between first cousins, is associated with increased rates of autosomal recessive genetic disorders. Research shows that children born from these unions are at significantly higher risk of severe disabilities and lifelong health complications, often requiring complex and costly treatment.

To investigate this further, FOI requests were submitted to NHS Trusts in Birmingham, Bradford, and Luton — three regions known to have high rates of cousin marriage in specific communities. This was a strategic decision, grounded in demographic data and previous academic research. Birmingham and Bradford, in particular, have been the focus of prior studies, including the Born in Bradford project and regional NHS consanguinity guidance.

Luton has not yet responded. But what has been received so far is revealing.

University Hospitals Birmingham NHS Foundation Trust FOI Reference: FOI 5362 Date: July 2025

In response to our FOI, the Trust confirmed:

• 1,559 patients were treated between 1 January 2020 and 1 June 2025 who had a diagnosis code of Z83.3: "Family history of other genetic and hereditary diseases, including consanguinity".

• The total cost of treating these patients was £3,608,438.45.

The costs include inpatient care, outpatient services, day cases, regular attenders, and related support across various specialties. The Trust extracted this data from their Cost Master System using the Z83.3 code.

However, the Trust explicitly stated:

“Please note that this does not mean that the treatment provided related to this diagnosis.” (FOI 5362)

This clarification is critical: while all 1,559 patients had family history of consanguinity recorded in their files, the treatment costs may not be directly related to conditions caused by consanguinity. Still, this represents a substantial group with a shared familial risk factor.

Bradford Teaching Hospitals NHS Foundation Trust FOI Reference: 25231 Date: July 2025

In contrast, the Bradford Trust was unable to provide figures on the number of patients or costs. Their response noted:

“The coding cannot differentiate between genetic disorders and the cause of those genetic disorders (i.e. those which are attributable to consanguinity). Identifying relevant cases would require a manual review of individual patient records, which would exceed the appropriate cost and time limits under the Freedom of Information Act.”

Further:

• No cost data is held on consanguinity-linked cases.

• No internal assessments, audits, or clinical planning documents were found that discuss the service burden.

• The Trust referred instead to external research including the Born in Bradford study and the Genes & Health briefing.

This is surprising for a city like Bradford, long identified in national and academic research as having one of the highest rates of cousin marriage in the UK.

This is not a fringe issue

In some areas of England, between 30–60% of children from certain ethnic backgrounds are born to first cousins. According to academic literature, this increases the risk of recessive genetic disorders by up to tenfold.

This is costing the NHS millions

With Birmingham alone reporting over £3.6 million in recorded costs linked to patients with a family history of consanguinity, it is reasonable to believe the national figure may stretch into the tens or even hundreds of millions when extrapolated across other high-prevalence regions.

There is no national audit or strategy

There is currently no national system to track or assess the impact of consanguinity-linked disorders on the NHS. Most Trusts do not even appear to conduct internal audits on the issue. Bradford, despite its demographics, holds no internal review material.

If you work inside the NHS or a government agency and have internal documents, whistleblower tip-offs, or unpublished data on this issue, get in touch securely: tipslewisbrackpool@proton.me

This investigation is ongoing. If you would like to watch the report, you can do so below; otherwise, you can view the documentation via my Proton Drive here.