by Dr. Chris Vorster – Chemical Pathologist, Head: Centre for Human Metabonomics, North-West University
PATHCHAT Edition No. 6
Please contact your local Ampath pathologist for more information.
What is Newborn Screening (NBS)?
Newborn screening (NBS) is a public health measure aimed at the early detection, diagnosis, and management of selected inherited diseases.
🔹 Why is it important?
- Early diagnosis & treatment prevent severe disabilities and early death.
- Screening ensures optimal development, allowing affected individuals to live normal, productive lives.
- Cost-effective in the long run, reducing the financial burden on healthcare systems and families.
History of Newborn Screening
Newborn screening originated in the 1960s, with Dr. Robert Guthrie developing a test for Phenylketonuria (PKU).
🔹 Key milestones:
- 1950s: Identified that PKU-related neurotoxicity could be prevented through early dietary intervention.
- 1958-1962: Guthrie’s bacterial inhibition assay detected PKU in dried blood spots from newborns.
- By 1967: 35 U.S. states had mandatory newborn screening laws.
- Today: Most developed and developing nations (except much of Africa) have national screening programs.
🔹 Impact of Mass Spectrometry
- Tandem mass spectrometry (MS/MS) revolutionized screening, enabling simultaneous detection of multiple metabolic disorders.
- Expanded newborn screening now includes metabolic, endocrine, immune, and hematological disorders.
Newborn Screening in South Africa
There is a perception that inherited metabolic diseases (IMDs) are rare in South Africa, but this is incorrect.
Findings from South African Studies
- Hitzeroth et al. (1995): Found 1 case of PKU and 1 case of tyrosinemia among 60,000 screened newborns, concluding IMDs were too rare for screening.
- Van der Watt et al. (2010): Predicted an incidence of 1 in 5,000 for glutaric acidemia type I in South African black populations, one of the highest worldwide.
- Prof. LJ Mienie (North-West University): Over 50,000 metabolic workups identified frequent IMDs, including:
- Isovaleric acidemia
- Propionic acidemia
- Galactosemia
- Vitamin B-responsive methylmalonic acidemia
- Maple syrup urine disease
- Glutaric acidemia type I
🔹 Genetic and congenital disorders are present across all populations, regardless of ethnicity or socioeconomic status.
Economic Considerations of Newborn Screening
A major concern against screening is the perceived cost. However:
🔹 Screening is more cost-effective than treating late-diagnosed conditions that result in:
- Lifelong disabilities
- Hospitalization and specialized care
- High morbidity and mortality
🔹 Economic reality:
- Screening costs are immediate, but benefits are long-term.
- Many developing countries use pilot programs before implementing nationwide screening.
🔹 Comparison of Screening Implementation (GDP per Capita & Screening Coverage):
Country2011 GDP per Capita (USD)Newborn Screening CoverageEgypt6,50075% (2007)China8,30025% (2006)Thailand9,40097% (2006)Brazil11,80080% (2005)South Africa11,000<1% (2012)
Challenges for Clinicians Offering Newborn Screening in South Africa
🔹 1. Lack of National Policy & Medical Aid Support
- No official NBS policy → Most medical insurances do not reimburse screening.
- Patients question the validity of screening, leading to increased counseling workload for clinicians.
🔹 2. False Positives & Parental Anxiety
- False-positive rate ≈ 3% (CDC recommendation) → Balances missed cases vs. unnecessary follow-ups.
- For every true case detected, 100 false positives may occur, requiring follow-ups and repeat testing.
🔹 3. Cost of Confirmatory Testing
- Initial screening costs ≈ R700, but confirmatory tests can be expensive.
- Cap on confirmatory testing costs can help manage expenses.
- Scaling up requests for screening can make follow-up testing more affordable.
How to Improve Newborn Screening in South Africa
1. Increase Awareness & Training
- Request CPD presentations on NBS in your area.
- Train nurses and clinicians on pre/post-test counseling.
2. Implement Pilot Screening Programs
- Engage pathology practices to provide screening.
- Train designated staff to manage the process and counseling.
3. Collaborate with Local Institutions
- Work with universities and research centers to expand screening access.
- Use economies of scale to reduce costs for patients.
Newborn Screening at North-West University (NWU)
🔹 Established in 1999, evolving from the Metabolic Laboratory (30+ years of service).
🔹 Uses Tandem Mass Spectrometry (MS/MS) for advanced metabolic disorder screening.
🔹 Member of International Newborn Screening Networks.
🔹 Follows the American College of Medical Genetics (ACMG) guidelines.
Conditions Screened in the NWU Program
Disorder TypeExample ConditionsSymptomsAmino Acid DisordersPKU, Maple Syrup Urine DiseaseIntellectual disability, metabolic crisesOrganic AcidemiasPropionic acidemia, Glutaric acidemiaMetabolic acidosis, neurological damageFatty Acid Oxidation DisordersMCAD, VLCAD, LCHADSudden infant death, liver diseaseEndocrine DisordersCongenital Hypothyroidism, CAHGrowth failure, developmental delayOther DisordersCystic Fibrosis, Galactosemia, SCID*Chronic lung disease, recurrent infections
🚨 Note: SCID screening is not yet included but can be requested separately from Ampath.
Conclusion: The Future of Newborn Screening in South Africa
🔹 South Africa must develop national policies for systematic newborn screening.
🔹 Collaboration between clinicians, researchers, and healthcare providers is essential.
🔹 Early detection saves lives and reduces long-term healthcare costs.
"Newborn screening is not just a test – it is a lifelong investment in health."