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A spectrum of many different syndromes characterized by persistent multiple limb contractures. It is often associated with midline dysraphism abnormalities. Distal Arthrogryposis Type I and Type IIA (☞Freeman-Sheldon Syndrome) are the most common forms. Arthrogrypotic features are present in numerous syndromes and often associated with pharyngeal, cardiac, urologic, or gastric abnormalities.
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Synonyms and Syndromes included
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Multiple Congenital Articular Rigidity; Guérin-Stern Syndrome; Otto Syndrome; Rocher-Sheldon Syndrome; Rossi Syndrome; Congenital Arthromyodysplastic Syndrome; Myodysplasia Fetalis Deformans; Myodystrophia Fetalis Deformans.
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Varies from 0.3 to 3 cases per 1,000 live births. No racial or sexual predilection has been reported (except obviously for cases with X-linked transmission).
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Most cases are sporadic. More than 150 genes are known to be involved in different types of Arthrogryposis. Distal Arthrogryposis Type I and Type IIA are autosomal dominant inherited. The responsible mutations have been mapped to chromosome 9p13.3 (Type I) and 17p13.1 (Type IIA), respectively. Some syndromes in which Arthrogryposis is part of the clinical picture have X-linked transmission. Identical twins often are discordant for the condition, and the intrafamilial phenotype is highly variable.
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All forms of Arthrogryposis are associated with decreased fetal movement (fetal hypo-/akinesia), and the severity of the contractures is directly related to time of onset and duration of fetal hypo-/akinesia, ie, the earlier and longer intrauterine movement has been restricted, the more severe the contractures will be at birth.
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Several factors have been implicated in the etiology of AC:
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Neuropathic origin: Abnormal nerve formation, structure, and/or function may affect muscle function. The cause may originate from the central nervous system (eg, reduced number of anterior horn cells, demyelination of the pyramidal tract, or motor roots) or from peripheral nerves (eg, reduced number of axons).
Myopathic origin: Abnormalities in the muscular structure and/or function are known to negatively affect fetal movement and lead to joint deformities and contractures.
Neuromuscular endplate processes: Failure of the embryonic/fetal neuromuscular endplate to form and mature properly.
Connective tissue processes: May affect the bones (symphalangism, synostoses) or connective tissue itself (eg, joint capsule fibrosis, abnormal tendons, replacement of muscle tissue by fibrous tissue).
Space limitations: If fetal movement is restricted due to limited space (twin pregnancy, abnormal uterus (eg, uterus bicornis, uterine tumors), oligohydramnios), then movement becomes typically more restricted later on in pregnancy. These contractures often respond well to early postnatal physiotherapy.
Maternal factors (eg, multiple sclerosis, maternal diabetes, myasthenia gravis, myotonic dystrophy) could potentially result in multiple congenital contractures. The same applies to maternal infections (eg, rubella, measles, Coxsackie virus), exposure to certain drugs during pregnancy (eg, phenytoin, phenobarbital, cocaine, alcohol), and preexisting maternal metabolic anomalies.
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Experienced sonographers may already detect fetal hypo-/akinesia early on in pregnancy ...