What is the role of lab tests in the workup of arthrogryposis multiplex congenita (AMC)?

Updated: Nov 11, 2020
  • Author: Mithilesh Kumar Lal, MD, MBBS, MRCP, FRCPCH, MRCPCH(UK); Chief Editor: Maria Descartes, MD  more...
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Answer

See the list below:

  • Obtain creatine phosphokinase (CPK) levels when the following conditions are present:

    • Generalized weakness

    • Doughy or decreased muscle mass

    • Progressive worsening

  • Viral cultures may reveal an infectious process.

  • Immunoglobulin M levels and specific viral titers (eg, coxsackievirus, enterovirus) in the newborn may reveal intrauterine infection.

  • Maternal antibodies to neurotransmitters in the infant may point to the presence of myasthenia gravis.or recurrent affected pregnancies without diagnosis.

  • Patients should undergo genetic evaluation and genetic workup that includes, but is not be limited to, chromosome studies/comparative genomic hybridization (CGH) array analysis.

  • Cytogenetic study is indicated in the following situations:

    • Multiple organ or system involvement

    • Presence of CNS abnormalities, such as microcephaly, intellectual disability, lethargy, degenerative changes, or eye anomalies

  • Consider performing a fibroblast chromosome study if lymphocyte chromosome levels are normal and the patient has intellectual disablity without diagnosis.

  • Nuclear DNA mutation analysis is used to identify certain disorders, such as spinal muscular dystrophy.

  • Mitochondrial mutation analysis is used to identify certain disorders, such as mitochondrial myopathy.

  • Metabolic screening can be conducted in patients with hepatosplenomegaly, renal dysfuction, cholestasis, liver anomalies, hydrops, failure to thrive, or hypotonia.


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