Hypertelorism: nosologic analysis of 90 patients.

The word hypertelorism is used to describe increased interorbital distance, a condition that is causally and pathogenically heterogeneous. Because not all wide-set eyes are the same, accurate terminology and nosology are critical to understanding and management. Orbital hypertelorism signifies an increased distance between both medial sides and lateral sides of the orbits. Interorbital hypertelorism denotes increased distance only between the inner orbital walls. In this retrospective analysis of 90 patients with hypertelorism, the most common cause was frontonasal malformation (n = 30), a heterogeneous category of nonfamilial disorders including a newly described subgroup, rugose frontonasal malformation. The second most common cause was craniofrontonasal dysplasia (n = 18), a genetic syndrome comprising coronal synostosis, frontonasal anomalies, "frizzy" hair, narrow/sloping shoulder girdle deformity, and longitudinal ridging of nails in association with various truncal and extremity anomalies. Paramedian craniofacial cleft(s) (n = 10) and (sincipital) encephalocele (n = 6) were infrequent causes of hypertelorism. The fifth, miscellaneous category comprised well-defined, mostly chromosomal and syndromic disorders (n = 26). Patients in the various diagnostic categories were designated as having either orbital or interorbital hypertelorism. Hypertelorism also was graded as either first, second, or third degree based on deviation from age- and gender-matched normative data. The etiology and type of hypertelorism influence the selection of operative procedure, whereas the grade of severity indicates the need for surgical correction.