X-linked fetal akinesia syndrome

X-linked fetal akinesia syndrome, also known as X-linked lethal arthrogryposis with intrauterine growth retardation (IUGR), is an extremely rare and severe genetic disorder characterized by markedly reduced or absent fetal movement during pregnancy. This condition predominantly affects males and is caused by mutations in genes on the X chromosome. The syndrome falls within the broader spectrum of fetal akinesia deformation sequence (FADS), in which lack of fetal movement leads to a cascade of secondary developmental abnormalities. The hallmark features include severe arthrogryposis multiplex congenita (multiple joint contractures), intrauterine growth restriction, fetal hydrops (abnormal fluid accumulation), pulmonary hypoplasia (underdeveloped lungs), and characteristic facial anomalies such as a small jaw (micrognathia) and low-set ears. Polyhydramnios (excess amniotic fluid) is frequently observed during pregnancy due to impaired fetal swallowing. The musculoskeletal, respiratory, and central nervous systems are primarily affected. Thin, gracile bones and decreased muscle mass are commonly noted. Pterygia (skin webbing across joints) and cystic hygroma may also be present. The prognosis is extremely poor, with most affected males dying in utero or shortly after birth, primarily due to respiratory failure from pulmonary hypoplasia. Female carriers are typically unaffected or may show very mild features. There is currently no curative treatment available. Management is supportive and palliative. Genetic counseling is essential for affected families, and prenatal diagnosis may be possible through ultrasound detection of reduced fetal movements and molecular genetic testing when the causative mutation has been identified in the family.

Common questions about X-linked fetal akinesia syndrome