Arthrogryposis, or arthrogryposis multiplex congenita (AMC), is characterized by the presence of non-progressive multiple joint contractures in different areas of the body present from birth.
It is estimated that up to 1% of newborns are born with some type of congenital contracture, although the prevalence of arthrogryposis is estimated in 1/3 000 live births (Lowry et al., 2010). Approximately two thirds of affected individuals can be diagnosed by the age of two, and great progress is being made in the identification of specific genetic and non-genetic causes of arthrogryposis (Hall et al., 2014). It has been estimated that a genetic cause can be identified in approximately 30% of cases (Dimitraki et al., 2011).
There are different forms that should be considered when selecting the genetic study:
- Amyoplasia or “classic arthrogryposis” accounts for one third of cases, with a prevalence of 1/10 000 live births. They are sporadic cases with all four limbs affected, unaffected trunk, and no multisystem involvement. They usually do not have a genetic cause, and their etiology is due to maternal-fetal factors in pregnancy. However, some forms can clinically resemble distal forms of arthrogryposis. Therefore, prior to a genetic study request, cases must be carefully selected based on clinical suspicion and potential differential diagnoses
- Those individuals with associated CNS involvement (malformations, intellectual disability, or other developmental disorders) or dysmorphic features require an assessment involving chromosomal and gene dosage studies (karyotype, SNP-arrays, etc.).
- Targeted genetic studies are more adequate and have a higher yield for distal arthrogryposis and multiple pterygium-associated conditions, for which we have developed specific panels
- It is worth noting that up to 5% of arthrogryposis cases are secondary to myopathies and congenital myasthenic syndromes (Darras et al., 2015), which are targeted by the arthrogryposis comprehensive panel