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Hypertelorism

Summary   Ultrasound Features   Differential Diagnoses   Syndromes   Show All

Summary Orbital hypertelorism is defined as excessive separation of the medial walls of the bony orbit. This dimension should always be considered in relationship to overall head size, since excessive spacing of the orbits in a head greater than two standards above the mean may be considered normal. After birth, radiological assessment of the bony interorbital distance is the most accurate method to determine whether excessive eye spacing is present. However, interpupillary distance is the optimum dimension used in clinical determination of eye-spacing. This measurement may have ultrasonographic relevance in the future, particularly as a transvaginal approach allows visualisation of the fetal lens. During early embryonic life, the eyes grow laterally on optic stalks, and then move towards the midline. Several mechanisms have been proposed to explain the development of orbital hypertelorism. Firstly, there may be morphokinetic arrest that causes failure of migration of the orbits to the midline with some time-specific deficiency in differential growth. Secondly, interruption of migration might occur because a primary midline lesion, such as an encephalocele, inhibits approximation of the orbits. Thirdly, a pathological process affecting the cranial base, for example, secondary to craniosynostosis, could lead to separation of the orbits.Although orbital imaging is not routine in most centres, and is not included in the AIUM guidelines for obstetrical ultrasonography, the bony orbits are reliably imaged when scanning the fetal face from the 12th week onward. Care must be taken to avoid tangential cuts through the orbits. The inner orbital measurement is most useful in the determination of hypertelorism, and is generally greater than two standard deviations from the mean. The outer orbital measurement often falls at the 95th percentile. With the head in the occipitotransverse position, the transducer can be placed in two possible planes, firstly, along the coronal plane, approximately 2 cm posterior to the glabella-alveolar line, or, secondly, along the orbitomeatal line, approximately 2 to 3 cm below the level of the biparietal diameter. In both these views, the midline, orbital rings, nasal processes, and portions of the maxilla can be demonstrated. The inner and outer orbital diameters are measured from the leading edge to falling edge; outer diameter from lateral border of one bony orbit to lateral border of the other bony orbit, inner diameter from medial border to medial border. Occasionally, when the head is in this position, it is difficult to define accurately the distal orbital margin because of acoustic shadowing from the nose. With the head in the occipitoposterior position, a biparietal diameter cannot be obtained. However, the orbits can be identified and measured with the transducer placed in a plane that transects the occiput, orbits and nasal processes. Measurements should only be obtained when the fetal face is perpendicular to the uterine wall, since measurements in an oblique plane may be unreliable. The optimal view of the fetal eyes on transvaginal ultrasonography is a transverse section of the fetal skull at the orbital plane. The eyes within the bony orbits are detected as bilateral hypoechoic circles superolateral to the nasal bones. A detailed search for intra- and extra-cranial anomalies should be performed since these are frequently associated with differences in eye spacing, and may provide evidence for a particular malformation syndrome, as detailed in the table of associated syndromes. Prenatal diagnosis has been reported in Opitz, Crouzon , Apert and median cleft face (frontonasal dysplasia) syndromes. Title: Orbital diameters: a new parameter for prenatal diagnosis and dating Author: Mayden KL, Tortora M, Berkowitz RL, Bracken M, Hobbins JC Journal: Am J Obstet Gynecol 144: 289-297 Year: 1982 Title: Fetal ocular biometry by ultrasound Author: Jeanty P, Dramaix-Wilmet M, Van Gansbeke D, Van Regemorter N, Rodesch F Journal: Radiology 143: 513-6 Year: 1982 Title: Significance of orbital measurements in the fetus Author: Trout T, Budorick NE, Pretorius DH, McGahan JP Journal: J Ultrasound Med 13: 937-43 Year: 1994 Title: First- and second-trimester diagnosis of fetal ocular and associated anomalies: report of eight cases Author: Bronshtein M, Zimmer E, Gershoni-Baruch R, Yoffe N, Meyer H, Blumenfeld Z Journal: Obstet Gynecol 77: 443-9 Year: 1991 Title: Prenatal diagnosis of Opitz (BBB) syndrome in the second trimester by ultrasound detection of hypospadias and hypertelorism Author: Hogdall C, Siegel-Bartelt J, Toi A, Ritchie S Journal: Prenat Diagn 9: 783-793 Year: 1989 Title: Antenatal diagnosis of median cleft face syndrome: sonographic demonstration of cleft lip and hypertelorism Author: Chervenak FA, Tortora M, mayden K, Mesologites T, Isaacson G, Mahoney MJ, Hobbins JC Journal: Am J Obstet Gynecol 149: 94-7 Year: 1984 Title: Interstitial deletion of chromosome 1 del (1) (q32q42): case report and review of the literature Author: Sarda P, Lefort G, Taviaux S, Humeau C, Rieu D Journal: Clin Genet 41: 25-7 Year: 1992 Title: Oral and dental development in X chromosome aneuploidy Author: Farge P, Dallaire L, Albert G, Melancon SB, Potier M, Leboeuf G Journal: Clin Genet 27: 122-6 Year: 1985 Title: Apert syndrome, an antenatal ultrasound detected case Author: Parent P, Le Guern H, Munck MR, Thoma M Journal: Genetic Counselling 5: 297-301 Year: 1994 Title: New X-linked syndrome of mental retardation, short stature, and hypertelorism Author: Stoll C, Geraudel A, Chauvin A Journal: Am J Med Genet 39: 474-8 Year: 1991 Title: Teebi hypertelorism syndrome: report of a third family Author: Toriello HV, Delp K Journal: Clin Dysmorph 3: 335-9 Year: 1994 Title: Letter to the editor: Frontofacionasal dysostosis - a new autosomal recessive syndrome Author: Gollop TR Journal: Am J Med Genet 10: 409-412 Year: 1981 Title: An aminopterin-like syndrome without aminopterin (ASSAS) Author: Fraser FC, Anderson RA, Mulvihill JI, Preus M Journal: Clin Genet 32: 28-34 Year: 1987 Title: Iris coloboma, ptosis, hypertelorism, and mental retardation: a new syndrome Author: Baraitser M, Winter RM Journal: J Med Genet 25: 41-3 Year: 1988 Title: Hirschsprung disease associated with polydactyly, unilateral renal agenesis, hypertelorism, and congenital deafness: a new autosomal recessive syndrome Author: Santos H, Mateus J, Leal MJ Journal: J Med Genet 25: 204-8 Year: 1988 Title: Iris coloboma, ptosis, hypertelorism, and mental retardation: a new syndrome possibly localised on chromosome 2 Author: Pallotta R Journal: J Med Genet 28: 342-4 Year: 1991 Title: Diaphragmatic hernia, exomphalos, absent corpus callosum, hypertelorism, myopia, and sensorineural deafness: a newly recognised autosomal recessive disorder? Author: Donnai D, Barrow M Journal: Am J Med Genet 47: 679-682 Year: 1993 Title: Sonographic appearance of craniofacial dysostosis (Crouzon syndrome) in the second trimester Author: Gollin YG, Abuhamad AZ, Inati MN, Shaffer WK, Copel JA, Hobbins JC Journal: J Ultrasound Med 12: 625-8 Year: 1993 Title: Hypertelorism in neurofibromatosis Author: Wolters EC, Westerhof W, Delleman JW, Dijkstra P Journal: Neuropediatr 17: 175-7 Year: 1986 Title: Ocular findings in Turner syndrome: a prospective study Author: Chrousos GA, Ross JL, Chrousos G, Chu FC, Kenigsberg D, Cutler G Jr, Loriaux DL Journal: Ophthalmology 91: 926-8 Year: 1984 Title: The facial profile in the diagnosis of fetal abnormalities Author: Turner GM, Twining P Journal: Clin Radiol 47: 389-395 Year: 1993 Title: In: Human Malformations and Related Anomalies Author: Traboulsi E Journal: Oxford University Press, p634-8 Year: 1993 Title: Craniofrontonasal dysplasia Author: Cohen MM Jr Journal: Birth Defects 15: 85-9 Year: 1979 Title: Hypertelorism, microtia and facial clefting: a newly described, inherited syndrome Author: Bixler D Journal: Am J Dis Child 118: 495-8 Year: 1969 Title: A new craniofacial disorder involving hypertelorism and malformations of external nose, palate and pituitary gland. Author: Kjaer I; Reintoft I; Poulsen H; Nolting D; Prause JU; Jensen OA; Fisher Hansen B Journal: J Craniofac Genet Dev Biol Jan-Mar;17(1):23-34 Year: 1997 Title: Prenatal diagnosis: evolution in craniofacial surgery. Author: De Ponte FS; Bottini DJ; Maggi E; Marchetti E; Cascone P; Iannetti G Journal: J Craniofac Surg Mar;9(2):190-5 Year: 1998 Ultrasound Features Inner orbital distance greater than two standard deviations above the mean for gestational age. Often accompanied by outer orbital distance at the upper limits of normal Differential Diagnoses Primary hypertelorism, due to lack of convergence of the bony orbits, should be differentiated from hypertelorism secondary to a midline lesion, such as a frontal encephalocele. Syndromes Aarskog Acrocallosal Acrodysostosis Aminopterin -like syndrome without aminopterin (ASSAS) Apert Baraitser-Winter Chromosome anomaly Coffin-Lowry Craniofrontonasal Crouzon DiGeorge Donnai Frontofacionasal dysplasia Frontonasal dysplasia Greig Hypertelorism-Microtia clefting LEOPARD Neurofibromatosis Noonan Opitz [G, BBB] Otopalatodigital Robinow Santos Sotos PLATYPUS TKI Medcon Inc. Copyright 1999. All Rights Reserved. Stoll Teebi Teratogen exposure

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