Congenital defects of this disorder include joint contractures that cause a clenched fist with overlapping fingers. For 10 points each:
[10h] Name this genetic disorder that causes various malformations including heart defects and rocker-bottom feet, and is the second most common trisomy disorder after Down syndrome.
ANSWER: Edwards syndrome [or trisomy 18]
[10e] Trisomy disorders like Edwards syndrome are scanned for during pregnancy using this technique. Echocardiography is a type of this technique, which uses high-frequency acoustic waves to look at the uterus.
ANSWER: prenatal ultrasound [or ultrasonography; accept ultrasonogram]
[10m] Edwards syndrome may cause a Dandy–Walker malformation, in which a portion of this structure called the vermis is absent. This structure is displaced down through the foramen magnum in a Chiari (“kee-AH-ree”) malformation, and receives information via mossy and climbing fibers.
ANSWER: cerebellum [accept cerebellum vermis or cerebellar tonsil; prompt on brain]
<Maryland B, Biology>