Clinical Biochemical Genetics

Historically, testing for inborn errors of metabolism (IEM) has been provided by research laboratories, each offering analyses only for disorders in line with their scientific interest. Today, hundreds of IEMs have been identified and Clinical Biochemical Genetics is now recognized as a laboratory discipline concerned with the evaluation and diagnosis of patients and families with inherited metabolic disease, monitoring of treatment, and distinguishing heterozygous carriers from noncarriers by metabolite and enzymatic analysis of physiological fluids and tissues.

The Biochemical Genetics Laboratory (BGL) at Mayo is an interdisciplinary group of laboratorians, geneticists, and pediatricians. The mission of BGL is to provide biochemical testing and result interpretation of the highest quality for the diagnosis, study, and clinical care of patients with IEMs, high risk of cardiac disease, malabsorption, and malnutrition disorders. The BGL routinely performs qualitative detection and quantitative determination of diagnostic markers based on a variety of manual, automated, and chromatographic methods, including MS/MS.

In 2001, the BGL performed more than 400,000 tests using over 159 different procedures, the majority of tests aimed to the biochemical diagnosis of IEM. Several of these procedures are screening tests, such as the analyses of amino acids, organic acids, and acylcarnitines, and are performed on specimens from patients presenting with symptoms reminiscent of an IEM (high-risk screening), to postmortem samples obtained primarily from children who died suddenly without apparent reason (postmortem screening). Prenatal diagnostic testing is also performed.

While there have always been discrepancies between the various state-mandated newborn screening programs, the inconsistent integration of MS/MS has widened the gap. Mayo's Biochemical Genetics Laboratory bridges the gaps in state screening programs by offering the Mayo Supplemental Newborn Screen (Test #82594) to interested hospitals. The BGL's proven expertise and collaborative agreement with Pediatrix Screening (an independent laboratory with experience in high-throughput newborn screening using MS/MS) enable Mayo to offer sensitive, specific, high-quality newborn screening. In addition, Mayo Medical Laboratories offers the benefit of a full spectrum of follow-up testing. Although the sensitivity and specificity of MS/MS in the identification of a detectable disorder is excellent and its positive predictive value higher than that of other technologies, it remains a screening test that requires further testing to confirm a disorder (usually on a sample other than a blood spot).