Home > Newborn Disorders > Short/branched chain acyl-CoA dehydrogenase deficiency
Short/branched chain acyl-CoA dehydrogenase deficiency
Names
Short/branched chain acyl-CoA dehydrogenase deficiency
SBCAD
2-methylbutrylglycinuria
2-methybutyryl CoA dehydrogenase deficiency
2MBCD deficiency
Overview
Deficiency of 2-methylbutyryl-CoA dehydrogenase results in inability to break down isoleucine causing an organic acidemia. This condition is found mostly by newborn screening and its clinical significance is still unclear. Some of the initially reported patients had neurological symptoms, but their relationship to the metabolic defect remains unclear.Prevalence
The condition is rare; less than 20 cases have been reported, primarily among the Hmong population. [Short/branched chain acyl-CoA dehydrogenase deficiency info for professionals (STAR-G)]Clinical Characteristics
With treatment, limited experience suggests sequelae may be avoidable. Without treatment, acute neonatal decompensation with neurologic deficits has been described. Most infants and children will not display symptoms in this rare disorder. Symptoms may be triggered by fasting or illness.Initial signs/symptoms may include:
- nausea
- vomiting
- irritability
- hypoglycemia
- lethargy
Treatment consists of carnitine supplementation and fasting avoidance. Again, the need for treatment is unclear and continued follow-up and monitoring of these patients seems at present the best course of action.
Follow-up on positive screening test
Quantitative plasma acylcarnitine profile, urine organic acids, urine acylglycine and acylcarnitine analysis. Urine acylglycine analysis is necessary to exclude this condition.Primary care management
Upon notification of the + screen
- Contact the family and evaluate the infant for poor feeding, lethargy, vomiting;
- Provide emergency treatment/referral for symptoms of vomiting, lethargy or seizures;
- To confirm the diagnosis, work with the following service(s): Utah Newborn Screening Program, (801-584-8256); See also Services below;
- For evaluation and ongoing collaborative management, consult the following service(s): Medical Genetics, (801-231-3599); See also Services below;
If the diagnosis is confirmed
- Educate the family regarding signs, symptoms, and the need for urgent care when the infant becomes ill (see Short/branched chain acyl-CoA dehydrogenase deficiency info for parents (STAR-G) for additional information);
- Assist in implementation of a low protein diet and avoidance of fasting;
- Oral L-carnitine may be indicated;
- For those identified after irreversible consequences, assist in management, particularly with developmental and educational interventions.
Specialty Care Collaboration
Initial consultation and ongoing collaboration, particularly for dietary management. Genetic counseling for the family.Resources
Information & Support
For Professionals
Short/branched chain acyl-CoA dehydrogenase deficiency info for professionals (STAR-G)
On the Screening, Technology and Research in Genetics (STAR-G) site, one of a series of Disorder Fact Sheets for Professionals;
structured list of information about the condition, with links to more information.
ACT Sheet for elevated C5 Acylcarnitine (ACMG)
(
348 KB)
Developed by the American College of Medical Genetics (ACMG), includes recommended responses to positive newborn screening
test results, diagnostic evaluation, clinical expectations, and sources of additional information. See the ACMG ACT Sheets
and Confirmatory Algorithms (link elsewhere on this page) for more info and sheets on other conditions.
ACT Sheets and Confirmatory Algorithms (ACMG)
The American College of Medical Genetics (ACMG) has developed ACTion (ACT) Sheets and algorithms for responding to positive
newborn screening test results. This page contains a table with links to all of the ACT Sheets and related algorithms.
Isovaleric acidemia Acute Illness Protocol (NECMP)
A guideline for healthcare professionals treating the sick infant/child who has previously been diagnosed with isovaleric
acidemia; developed under the direction of Dr. Harvey Levy, Senior Associate in Medicine/Genetics at Children’s Hospital Boston,
and Professor of Pediatrics at Harvard Medical School, for the New England Consortium of Metabolic Programs.
Short/branched chain acyl-CoA dehydrogenase (OMIM)
Extensive review of the genetic literature, from the Online Mendelian Inheritance in Man site, hosted by Johns Hopkins University,
providing technical information for providers on genetic disorders, links to MEDLINE, and links to other scientific information
and sites.
For Parents and Patients
Short/branched chain acyl-CoA dehydrogenase deficiency info for parents (STAR-G)
From the Screening, Technology and Research in Genetics (STAR-G) site, providing information for parents about short/branched
chain acyl-CoA dehydrogenase deficiency and links to other sites including parent support groups.
Organic Acidemia Association (OAA)
A non-profit organization that provides information for parents and providers; newsletters; event information; connections
with other parents; a listserv; a discussion board; information about nutrition and recipes; translation of their web pages
into five other languages; hosting of the Propionic Acidemia Research Network and other research funds; and links to other
sites.
Services
Newborn Screening Programs
Utah Newborn Screening Program,
more info...
44 Mario Capecchi Drive
Salt Lake City, UT 84114
Phone: 801-584-8256
Fax: 801-536-0966
http://health.utah.gov/newbornscreening
Pediatric Medical Genetics
See all Pediatric Medical Genetics services providers (3) in our database.
For other services related to this condition, browse our Services categories or search our database.
Helpful Articles
Alfardan J, Mohsen AW, Copeland S, Ellison J, Keppen-Davis L, Rohrbach M, Powell BR, Gillis J, Matern D, Kant J, Vockley J.
Characterization of new ACADSB gene sequence mutations and clinical implications in patients with 2-methylbutyrylglycinuria
identified by newborn screening.
Mol Genet Metab.
2010;100(4):333-8.
PubMed abstract / Full Text
These findings confirm that SBCAD deficiency can be identified through newborn screening by acylcarnitine analysis. Our patients
have been well without treatment and call for careful follow-up studies to learn the true clinical impact of this disorder.
Authors
| Reviewing Author: | Nicola Longo MD, PhD, 7/2011 |
| Compiled and edited by: | Alfred Romeo RN, PhD, 3/2007 |
| Content Last Updated: | 7/2011 |