Holoprosencephaly-hypokinesia syndrome is an extremely rare and fatal central nervous system malformation occurring during embryogenesis, presenting prenatally with holoprosencephaly and fetal hypokinesia as major features. Other manifestations include microcephaly, multiple contractures and intrauterine growth restriction. There have been no further descriptions in the literature since 1988.

In the resting position, the tip of the thumb is on, or near, the palm, close to the base of the fourth or fifth finger.