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PubMed This is a summary of 11 peer-reviewed journal articles Updated
Pediatrics

Symptoms and the Medical Debate

At a Glance

Most infants diagnosed with Short chain acyl-CoA dehydrogenase deficiency (SCADD) remain completely healthy. While older studies linked SCADD to severe symptoms, modern medical experts now consider it a benign biochemical trait rather than a true clinical disease.

If you search the internet for SCADD, you may find older medical reports that list scary symptoms like developmental delay, seizures (epilepsy), or low muscle tone (hypotonia) [1][2]. This can be incredibly frightening for a new parent. However, it is vital to understand that the medical community’s view of these symptoms has shifted dramatically in recent years [3].

The “Coincidence” Problem

In the early days of metabolic testing, doctors usually only tested children who were already showing symptoms like developmental delays [4]. When they found SCADD markers in these children, they assumed SCADD was the cause.

Today, we know there is a major flaw in that logic: common ACADS variants (like c.625G>A and c.511C>T) are extremely common in the general healthy population [5].

  • A Common Signature: Millions of healthy people carry these variants and have the “biochemical signature” of SCADD without ever knowing it [3][4].
  • Coincidental Findings: If a child has a developmental delay for an entirely different reason (such as a different genetic factor or birth complication) and also happens to have these common SCADD variants, doctors in the past mistakenly blamed SCADD [4][3].

The Current Expert Consensus

Modern studies that follow babies identified through newborn screening (who were healthy at birth) tell a much more reassuring story [6][7].

  • Asymptomatic Majority: The vast majority of infants identified via screening stay completely healthy and show normal growth and development [8][9].
  • A “Biochemical Entity”: Most experts now categorize SCADD as a biochemical entity or a “phenotype”—meaning it is a measurable laboratory trait—rather than a clinical disease [3][4].
  • Doubtful Clinical Ramifications: For the most common genetic forms of SCADD, researchers now believe the clinical impact is “doubtful” or non-existent [4].

Are There “True” Cases of SCADD?

While the consensus is that SCADD is generally benign, doctors remain cautious. There may be very rare cases involving specific, severe genetic mutations (not the common variants) that could potentially cause symptoms [1][10]. However, even in these rare instances, the symptoms are often mild and the prognosis remains optimistic [6][9].

Why This Matters for Your Baby

Because the markers for SCADD are so common, a positive screen is rarely a reason for medical intervention. If a child with SCADD does experience a health challenge like a developmental delay, modern specialists will often look for other causes rather than assuming SCADD is to blame, knowing that the biochemical profile is likely just an incidental finding [11][3].

Your baby’s positive screen is a record of how their body processes certain fats, but for nearly every child, it is not a prediction of their future health or abilities [3][6].

Common questions in this guide

Why do older medical reports say SCADD causes severe symptoms?
Early metabolic testing primarily focused on children who were already sick with issues like developmental delays. Doctors found SCADD markers and mistakenly blamed them, but we now know those children simply had common, harmless genetic variants alongside unrelated health issues.
Is SCADD considered a serious disease?
Today, most medical experts classify SCADD as a benign biochemical entity rather than a dangerous clinical disease. The vast majority of infants identified with this condition through newborn screening remain completely healthy and show normal development.
What does it mean if my baby has the c.625G>A or c.511C>T genetic variant?
Genetic variants such as c.625G>A and c.511C>T are incredibly common in the general, healthy population. Millions of people carry these variants without ever experiencing symptoms, so they are not an accurate predictor of future health problems.
If my child develops a delay later on, is SCADD to blame?
Because SCADD markers are so common in the general population, modern pediatric specialists will usually look for other underlying causes. They understand that the SCADD biochemical profile is likely just an incidental finding rather than the root cause of the delay.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Why is there such a big difference between what I read online about SCADD symptoms and what you are telling me?
  2. 2.If my baby has the common c.625G>A or c.511C>T variants, how likely is it that they will ever show symptoms?
  3. 3.How common are these genetic variants in the general population?
  4. 4.If my baby does experience a developmental delay later on, would you still attribute it to SCADD, or would we look for other causes?
  5. 5.Based on the current expert consensus, is my baby considered 'sick' or just 'biochemically unique'?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (11)
  1. 1

    Microcephaly and developmental delay caused by short-chain acyl-CoA dehydrogenase deficiency.

    Kılıç M, Şenel S, Karaer K, Ceylaner S

    The Turkish journal of pediatrics 2017; (59(6)):708-710.

    PMID: 30035407
  2. 2

    Novel and Recurrent ACADS Mutations and Clinical Manifestations Observed in Korean Patients with Short-chain Acyl-coenzyme a Dehydrogenase Deficiency.

    Kim YM, Cheon CK, Park KH, et al.

    Annals of clinical and laboratory science 2016; (46(4)):360-6.

    PMID: 27466294
  3. 3

    Diverse and unselected adults with clinically relevant ACADS variants lack evidence of metabolic disease.

    Breilyn MS, Kenny EE, Abul-Husn NS

    Molecular genetics and metabolism 2023; (138(1)):106971 doi:10.1016/j.ymgme.2022.106971.

    PMID: 36549199
  4. 4

    Tread carefully: A functional variant in the human NADPH oxidase 4 (NOX4) is not disease causing.

    Nafisinia M, Menezes MJ, Gold WA, et al.

    Molecular genetics and metabolism 2018; (123(3)):382-387 doi:10.1016/j.ymgme.2018.01.007.

    PMID: 29398271
  5. 5

    Fluxomic evidence for impaired contribution of short-chain acyl-CoA dehydrogenase to mitochondrial palmitate β-oxidation in symptomatic patients with ACADS gene susceptibility variants.

    Dessein AF, Fontaine M, Joncquel-Chevalier Curt M, et al.

    Clinica chimica acta; international journal of clinical chemistry 2017; (471()):101-106 doi:10.1016/j.cca.2017.05.026.

    PMID: 28532786
  6. 6

    Clinical characteristics and related gene mutations of infants with short-chain acyl-CoA dehydrogenase deficiency by neonatal screening in Beijing.

    Gong L, Yang N, Zhao J, et al.

    Zhejiang da xue xue bao. Yi xue ban = Journal of Zhejiang University. Medical sciences 2022; (51(3)):278-283 doi:10.3724/zdxbyxb-2022-0214.

    PMID: 36207829
  7. 7

    [Clinical, biochemical and gene mutation characteristics of short chain acyl-coenzyme A dehydrogenase deficiency by neonatal screening].

    Huang XW, Zhang Y, Yang JB, et al.

    Zhonghua er ke za zhi = Chinese journal of pediatrics 2016; (54(12)):927-930 doi:10.3760/cma.j.issn.0578-1310.2016.12.011.

    PMID: 27938594
  8. 8

    Newborn screening, genetic analysis, and long-term follow-up of 89 cases with short-chain acyl-CoA dehydrogenase deficiency (SCADD).

    Qian G, Liu C, Xu Y, et al.

    Molecular genetics and metabolism reports 2026; (46()):101292 doi:10.1016/j.ymgmr.2026.101292.

    PMID: 41716778
  9. 9

    Compound heterozygous mutations of ACADS gene in newborn with short chain acyl-CoA dehydrogenase deficiency: case report and literatures review.

    An SJ, Kim SZ, Kim GH, et al.

    Korean journal of pediatrics 2016; (59(Suppl 1)):S45-S48 doi:10.3345/kjp.2016.59.11.S45.

    PMID: 28018444
  10. 10

    Clinical relevance of short-chain acyl-CoA dehydrogenase (SCAD) deficiency: Exploring the role of new variants including the first SCAD-disease-causing allele carrying a synonymous mutation.

    Tonin R, Caciotti A, Funghini S, et al.

    BBA clinical 2016; (5()):114-9 doi:10.1016/j.bbacli.2016.03.004.

    PMID: 27051597
  11. 11

    Turkish case of ethylmalonic encephalopathy misdiagnosed as short chain acyl-CoA dehydrogenase deficiency.

    Bulut FD, Kör D, Şeker-Yılmaz B, et al.

    Metabolic brain disease 2018; (33(3)):977-979 doi:10.1007/s11011-017-0152-8.

    PMID: 29159724

This page discusses the medical consensus regarding SCADD symptoms for educational purposes only. Always consult your pediatrician or a metabolic geneticist about your baby's specific newborn screening results.

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