Impact case study database

The difference between incidence and detection of inborn errors of metabolism is dependent on the ability of the clinician to first suspect a rare disease and secondly confirm both the phenotype and genotype. For the patients and families of those suffering with rare conditions, a diagnosis means an opportunity for early treatment e.g., by CDCA in the case of CTX and oxysterol 7α-hydroxylase deficiency, and an end to the uncertainty and lack of information around treatment measures and outcomes, opening avenues for connection with support groups. Many inborn errors of metabolism do not yet have a specific therapy, so for the clinician a confirmed phenotype allows potential treatments to be tried and tested.

The EADSA technology has been used to identify key sterol metabolites and bile acid precursors in patient samples. The unique technology and expertise of Griffiths and Wang, which they offered without charge, has helped to confirm biochemical phenotypes of, and improve the selection of treatments for and the management of 70 patients with a range of rare inborn errors of cholesterol metabolism across Europe, Asia and the U.S ( Table 1).

Table 1 The number of individual patients per disease benefitting from biochemical diagnosis from the Griffiths-Wang group, 2014-2020. The prevalence, where known, is included for context of the rarity of each condition (data from OMIM).

These patients can now be more confidently diagnosed and better treated, and their disease is better managed through the application of this novel patented technology. Specific examples of the impact the research has had within disease states are presented below:

SPG5

SPG5 is a rare condition with unknown prevalence that is caused by mutations in the CYP7B1 gene, which controls the production of the enzyme oxysterol 7α-hydroxylase, a key enzyme in steroid metabolism in the brain. A deficiency in this enzyme leads to a wide range of signs and symptoms, most notably neurodegeneration and movement problems. In infants, the deficiency may present with liver disease, in which case it is referred to as oxysterol 7α-hydroxylase deficiency.

In 2016 Professors Griffiths and Wang “greatly assisted in characterizing the biochemical phenotype (sterol profile) of a Cypriot patient with spastic paraplegia, in particular a patient with novel, bi-allelic CYP7B1 mutations causing SPGA5A”. This was the first Cypriot patient identified with this condition [C1].

In Athens, the Griffiths-Wang laboratory was instrumental between 2016 and 2017 in the successful treatment of a 22-year-old patient with SPG5. The laboratory measured sterols in monthly blood and urine samples over a period of 18 months to track the patient’s response to treatment with chenodeoxycholic acid (CDCA). The clinicians confirmed that “the procedure performed helped considerably in the treatment of the patient and the biochemical profile in response to CDCA treatment” [C2].

Between 2013 and 2014 in collaboration with clinicians at Great Ormond Street Hospital and UCL Institute of Child Heath, who were treating a young patient presenting with liver disease, and suffering from oxysterol 7α-hydroxylase deficiency, the Swansea group monitored the biochemical response to treatment with CDCA. The therapy was successful. [C3].

ACOX2 Deficiency

ACOX2 deficiency is an exceptionally rare disease with less than five cases reported world-wide, it arises from mutations in the ACOX2 gene coding a peroxisomal enzyme involved in the sidechain shortening of bile acid precursors, a necessary step in the biosynthesis of primary bile acids. ACOX2 deficiency is an autosomal recessive disorder presenting to differing extents with cholestatic liver disease and neurologic dysfunction in infants and children.

In 2018, Griffiths and Wang used their EADSA technology to define the biochemical phenotype of Turkish patients suspected to have ACOX2 deficiency and “ for the first time, a previously unknown syndrome caused by recessive Acyl CoA Oxidase 2 deficiency has been identified with the great help of Professor William J. Griffiths from Swansea University Medical School in UK. Prof. Griffiths and his laboratory have greatly contributed to both the diagnosis and follow-up of the new disease by performing urine, serum and plasma bile acid analysis” [C4].

Lysosomal Acid Lipase Deficiency (LALD, Wolmans) Cholesterol 25-Hydroxylase Deficiency and Other Sterol-Related Disorders.

Caused by mutations in the LIPA gene, LALDs are rare inherited disorders about which little is known of the signs, symptoms, and progression. Wolmans disease is a LALD characterised by a complete absence of the LIPA protein. LALDs result in problems with lipid metabolism and the accumulation of harmful amounts of lipids in cells and tissues throughout the body, which subsequently causes liver disease.

In 2017 in collaboration with the Genomic Medicines team at St Mary’s Hospital in Manchester, the first ever patients with a double deletion of LIPA and of the adjacent gene CH25H, coding the enzyme cholesterol 25-hydroxylase, were identified using EADSA. Professors Griffiths and Wang were the first to biochemically confirm the enzyme deficiency in these children, and they have continued to “ look in detail at their sterolomic and oxysterol profiles of the LALD (and double deletion) patients before and after treatment with both Enzyme Replacement Therapy and Hemopoietic Stem Cell transplantation. This is proving a critical part in assessing the benefits of treatment” [C5]. Work with the team in Manchester has extended beyond LALDs and currently includes other rare lysosomal disorders Niemann-Pick type B and C diseases. Niemann-Pick disease can affect the brain, nerves, liver, spleen, bone marrow and lungs. There is no cure, but treatments are being developed. People with these conditions experience progressive loss of function of nerves, the brain and other organs. Other inborn errors of cholesterol metabolism being studied include, cerebrotendinous xanthomatosis (CTX), NSDHL deficiency and lathosterolosis. Less than five cases of lathosterolosis have been reported world-wide, the disorder is characterised by facial dysmorphism, congenital anomalies, failure to thrive, developmental delay and liver disease, there are treatments but no cure.

SLOS

SLOS is a severe autosomal recessive disorder resulting from defects in a cholesterol-synthesising enzyme that lead to a build-up of the cholesterol precursor 7-dehydrocholesterol in tissues and blood plasma. SLOS affects an estimated 1 in 20,000 to 60,000 newborns. Mildly affected individuals may have only minor physical abnormalities with learning and behavioural problems, but severe cases can be life-threatening and involve profound intellectual disability and major physical abnormalities, and there is no cure. Despite this, it is important for parents to have a diagnosis for their child and for clinicians to initiate treatments. Professors Griffiths and Wang have discovered a novel bile acid biosynthesis pathway in SLOS which may be responsible for the dysmorphology observed in this disease [R7]. Regarding these discoveries, collaborators at the Great Ormond Street Institute of Child Health stated “ Laboratories such as mine that can pick up unusual metabolites in children with significant disease really value the ability of Bill’s lab to identify the abnormal compound(s) we have detected” [C6].

Our EADSA methodology has also been used to diagnose SLOS at Hong Kong Queen Mary Hospital, where the medical technologist stated, “ I can successfully detect 7‐DHC in MS and I am so excited now!”, confirming that elevated 7-DHC provides a diagnosis of SLOS [C7].

The definitive diagnosis and monitoring of response to therapy provide peace of mind and hope to parents of those with IEM and allow clinicians to search for ever better therapies.