Microstomia is a clinical feature

Medical sign

A medical sign is an objective indication of some medical fact or characteristic that may be detected by a physician during a physical examination of a patient....

 of many craniofacial

Craniofacial

Craniofacial may be used to describe certain congenital malformations, injuries, surgeons who subspecialize in this area, multi-disciplinary medical-surgical teams that treat and do research on disorders affecting this region, and organizations with interest in...

 syndrome

Syndrome

In medicine and psychology, a syndrome is the association of several clinically recognizable features, signs , symptoms , phenomena or characteristics that often occur together, so that the presence of one or more features alerts the physician to the possible presence of the others...

s, including Freeman-Sheldon syndrome

Freeman-Sheldon syndrome

Freeman-Sheldon syndrome , also termed distal arthrogryposis type 2A , craniocarpotarsal dysplasia , Cranio-carpo-tarsal syndrome, Windmill-Vane-Hand syndrome, or Whistling-face syndrome, was originally described by Freeman and Sheldon in 1938...

 and Sheldon-Hall syndromes (or distal arthrogryposis multiplex congenita). It may present with whistling-face feature, as well, as in Freeman-Sheldon syndrome. In this syndrome, it impairs alimentation and may require repeated oral surgeries (called commissurotomy

Commissurotomy

A commissurotomy is a surgical incision of a commissure in the body, as one made in the heart at the edges of the commissure formed by cardiac valves, or one made in the brain to treat certain psychiatric disorders....

) to improve function.