Short/Branched Chain Acyl-CoA Dehydrogenase (SBCAD) Deficiency
Guidance for primary care clinicians receiving a positive newborn screen result
Description
Short/branched chain acyl-CoA dehydrogenase (SBCAD) deficiency is a disorder of isoleucine metabolism that is often found incidentally on newborn screening with an elevated C5 level. The clinical significance of this biochemical finding is to be determined - the majority of patients remain asymptomatic. Estimates suggest that approximately 10% of patients may develop symptoms, which can include variable onset from neonatal to early childhood with seizures, developmental delay, hypotonia, and failure to thrive. [Porta: 2019]
Clinical Characteristics
- Poor appetite
- Lethargy
- Irritability
- Developmental delays
- Poor growth
- Hypotonia
Incidence
Primary Care Management
Next Steps After a Positive Screen
- Contact the family and evaluate the infant for seizures, poor feeding, lethargy, and vomiting.
- Provide emergency treatment/referral as needed.
- Educate the family about signs/symptoms of metabolic acidosis (see above) and the need for urgent treatment if symptoms are present.
Confirming the Diagnosis
- To confirm the diagnosis of SBCAD deficiency, work with Newborn Screening Services (see NW providers [1]).
- Follow-up biochemical testing for suspected cases may include plasma acylcarnitine analysis to confirm the increased C5 and urine organic acids to identify 2-methylbutyrylglycine. Urine acylglycine may also be informative. Confirmation can also be made with genetic testing for ACADSB gene variants.
If the Diagnosis is Confirmed
- For evaluation and ongoing collaborative management, consult Biochemical Genetics (Metabolics) (see NW providers [1]).
- Educate the family regarding the signs and symptoms of metabolic acidosis and the need for urgent care when the infant becomes ill.
- Work with the metabolic specialist for evaluation and collaborative management.
Resources
Information & Support
Related Portal Content
After a Diagnosis or Problem is Identified
Families can face a big change when their baby tests positive
for a newborn condition. Find information about A New Diagnosis - You Are Not
Alone; Caring for Children with Special Health Care Needs; Assistance in
Choosing Providers; Partnering with Healthcare Providers; Top Ten Things to Do
After a Diagnosis.
For Professionals
2-Methylbutyryl-CoA Dehydrogenase Deficiency (OMIM)
Information about clinical features, diagnosis, management, and molecular and population genetics; from Online Mendelian Inheritance
in Man, authored and edited at the McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine
For Parents and Patients
Baby's First Test: 2-Methylbutyrylglycinuria
Information about early signs, follow-up testing, treatment, accessing care, and expected outcomes. Provides links to support
services.
2MBC (2-Methylbutyryl-CoA Dehydrogenase Deficiency) (STAR-G)
Very detailed information for families, including description, causes, outcomes, genetic testing, incidence, and more from
the Screening, Technology And Research in Genetics Project, begun by the Hawaii Department of Health and now maintained by
the Western States Regional Genetics Network.
2-Methylbutyryl-CoA Dehydrogenase Deficiency (GARD)
Includes information about symptoms, inheritance, diagnosis, finding a specialist, related diseases, and support organizations;
Genetic and Rare Diseases Information Center of the National Center for Advancing Translational Sciences.
Organic Acidemia Association (OAA)
A nonprofit organization that provides information, support, events, connections with other parents, a discussion board,
and nutrition and recipe ideas.
Tools
ACT Sheet for Elevated C5 Acylcarnitine (ACMG) (
290 KB)
Contains short-term recommendations for clinical follow-up of the newborn who has screened positive; American College of Medical
Genetics.
Confirmatory Algorithm for Elevated C5 (ACMG) ( 194 KB)
An algorithm of the basic steps involved in determining the final diagnosis of an infant with a positive newborn screen; American
College of Medical Genetics.
Services for Patients & Families Nationwide (NW)
| Service Categories | # of providers* in: | NW | Partner states (4) (show) | | NM | NV | RI | UT | |
|---|---|---|---|---|---|---|---|---|---|
| Biochemical Genetics (Metabolics) | 1 | 1 | 2 | 3 | 2 | ||||
| Newborn Screening Services | 1 | 3 | 2 | 2 | 3 | ||||
For services not listed above, browse our Services categories or search our database.
* number of provider listings may vary by how states categorize services, whether providers are listed by organization or individual, how services are organized in the state, and other factors; Nationwide (NW) providers are generally limited to web-based services, provider locator services, and organizations that serve children from across the nation.
Helpful Articles
Porta F, Chiesa N, Martinelli D, Spada M.
Clinical, biochemical, and molecular spectrum of short/branched-chain acyl-CoA dehydrogenase deficiency: two new cases and
review of literature.
J Pediatr Endocrinol Metab.
2019;32(2):101-108.
PubMed abstract
Page Bibliography
Porta F, Chiesa N, Martinelli D, Spada M.
Clinical, biochemical, and molecular spectrum of short/branched-chain acyl-CoA dehydrogenase deficiency: two new cases and
review of literature.
J Pediatr Endocrinol Metab.
2019;32(2):101-108.
PubMed abstract