Eye Findings in 8 Children and aSpontaneously Aborted Fetus WithRSH/Smith-Lemli-Opitz Syndrome

La-Ongsri Atchaneeyasakul,1 Leesa M. Linck,2,4 William E. Connor,3 Richard G. Weleber,1,2 andRobert D. Steiner2,4*1Department of Ophthalmology, Casey Eye Institute, Oregon Health Sciences University, Portland, Oregon2Department of Molecular and Medical Genetics, Oregon Health Sciences University, Portland, Oregon3Department of Medicine, Oregon Health Sciences University, Portland, Oregon4Department of Pediatric and Child Development and Rehabilitation Center, Doernbecher Children’s Hospital,Oregon Health Sciences University, Portland, Oregon

We evaluate the ophthalmologic findings in8 children with RSH/Smith-Lemli-Opitz syn-drome (SLOS) and document abnormal con-centrations of cholesterol and cholesterolprecursors in the ocular tissues in a case ofSLOS. The most common ophthalmologicfinding was blepharoptosis, which wasfound in 6 of 8 patients, with the severityranging from mild to moderate. None of thepatients in the present study demonstratedcataracts; none had amblyopia from blepha-roptosis. One patient had a right hypertro-pia with overaction of the inferior obliquemuscle. This patient also had optic atrophyand a second patient had bilateral opticnerve hypoplasia. The importance of thesefindings to the visual function remains to bedefined. Sterol analysis from ocular tissuesof an aborted fetus with SLOS showed in-creased 7- and 8-dehydrocholesterol and alow cholesterol concentration in the retinalpigment epithelium, lens, cornea, andsclera. Routine ophthalmologic examina-tion is indicated in SLOS because of thehigh incidence of abnormalities, most likelydue to the abnormal synthesis of cholesteroland cholesterol precursors in the ocular tis-sues of these patients, as evidenced by sterolanalysis of the ocular tissues in a case ofSLOS. Am. J. Med. Genet. 80:501–505, 1998.© 1998 Wiley-Liss, Inc.

KEY WORDS: RHS/Smith-Lemli-Opitz syn-drome; optic nerve hypopla-sia; optic atrophy

INTRODUCTION

In 1964, Smith et al. described a previously unrecog-nized autosomal recessive syndrome of multiple con-genital anomalies in three unrelated males. Theanomalies consisted of microcephaly with mental retar-dation and hypotonicity; growth retardation; shortnose with anteverted nostrils, broad maxillary alveolarridges, and mild micrognathia; incomplete develop-ment of the external genitalia; abnormal palmarcreases; foot anomalies consisting of metatarsus adduc-tus and/or syndactyly between the second and thirdtoes; and other variable anomalies. The abnormal oph-thalmologic findings included blepharoptosis, epican-thal folds, and internal strabismus. All three patientshad a normal chromosome number of 46 per cell withno aberration of an individual chromosome.

Thirty years later, Tint et al. [Irons et al., 1993; Tintet al., 1994] found low cholesterol and elevated 7-dehy-drocholesterol (7-DHC) in plasma of SLOS patientsand suggested the deficiency of 7-dehydrocholes-terol-D7-reductase as the cause of Smith-Lemli-Opitzsyndrome (SLOS). This enzyme converts 7-DHC to cho-lesterol. Deficiency of this enzyme results in lowplasma and tissue cholesterol and the unusual pres-ence of 7-DHC in the plasma and tissues. Deficiency ofthis enzyme in hepatic microsomes in SLOS was laterproven by the same group [Shefer et al., 1995].

Ophthalmologic findings in SLOS reported previ-ously include blepharoptosis, epicanthal folds, conver-gent strabismus, downslanting small palpebral fis-sures, mild exophthalmos, retinal pigment epithelialdefects, pale disks, nystagmus, microcornea, aniridia,congenital cataracts, postlenticular membrane, Du-ane’s retraction syndrome, absence of lacrimal puncta,

This material was presented as a poster presentation at theAmerican Society of Human Genetics (ASHG) meeting October27, 1997 to November 2, 1997.

*Correspondence to: Robert D. Steiner, M.D., Departments ofPediatrics and Child Development and Rehabilitation Center andMolecular and Medical Genetics, Oregon Health Sciences Univer-sity, 3181 SW Sam Jackson Park Road, Portland, Oregon 97201-3098.

Received 28 May 1998; Accepted 11 August 1998

American Journal of Medical Genetics 80:501–505 (1998)

© 1998 Wiley-Liss, Inc.

opsoclonus-like eye movements, lack of visual followingresponses and of opticokinetic reflexes, corneal en-largement, abnormal iris insertion, bilateral optic pits,sclerocornea and optic nerve demyelination [Opitz etal., 1969; Gold and Pfaffenbach, 1975; Harbin et al.,1977; Fierno et al., 1977; Freedman and Baum, 1979;Kretzer et al., 1981; Bardelli et al., 1985]. Becausethere is no published study that systematically docu-ments ophthalmologic findings in SLOS patients, weundertook a prospective study of 8 patients with SLOS.Biochemical sterol analysis was also undertaken froma globe of a spontaneously aborted fetus with SLOS inan attempt to elucidate the pathogenesis of ophthalmo-logic abnormalities in SLOS.

PATIENTS AND METHODSEight patients who carry the diagnosis of SLOS were

seen at Oregon Health Sciences University. All re-ceived a complete ophthalmologic examination. Age atthe diagnosis of SLOS, gestational age, birth weight,length at birth, head circumference, developmentalstatus, growth development, karyotype, and age at thebeginning of dietary cholesterol supplementation aresummarized in Table I. All patients underwent visualacuity measurement, cycloplegic refraction, strabismusevaluation, slit lamp biomicroscopy of the anterior seg-ment, and fundus examination. Fundus photographswere undertaken to verify and document the abnor-malities seen in 2 patients.

TABLE I. General Information on Eight Patients With Smith-Lemli-Opitz Syndrome*

K.B. C.A. M.S. J.C. R.H. A.L. B.B. A.S.

Sex F F F M F M M FAge at diagnosis of

SLOS (mo.)24 2 4 0.5 6 60 0.25 6

Age last exam (mo.) 40 13 27 3 36 64 1.25 60Gestational age

(wk)40 38 39 38.5 36 40 40 40

Birth weight (kg) 2.95 2.5 3.6 3.1 2.5 3.2 3.1 3.1(centile) (25th) (5–10th) (75th) (25–50th) (5–10th) (50th) (25–50th) (25–50th)Length (in) 18.5 19 20 19 17.75 18.5 19 19(centile) (10th) (25th) (75th) (10–25th) (5th) (5–10th) (25th) (25th)Head circ (cm) 32.5 — 33 34 31 — — —(centile) (5–10th) (10th) (25th) (<5th)Developmental

delay++ ++ ++ + +++ + N ++

Growth retardation(at last exam)

+++ +++ +++ N +++ N ++ +++

Other problems Poor feeding& failure tothrive ininfancy

Feedingproblemafter birth

Patent ductusarteriosus,feedingproblemafter birth

— Poorswallowing,& sucking,aortic &pulmonicstenosis

— Poor feedingin infancy

Poor feeding& failure tothrive ininfancy

Karyotype N — N — N — N —Age at beginning

of dietarycholesterolsupplementation(mo.)

33 3 4 1.5 28 144 1.25 41

*N indicates normal; + indicates mild; ++ indicates moderate; +++ indicates severe.

TABLE II. Ophthalmologic Findings in Eight Patients With Smith-Lemli-Opitz Syndrome*

K.B. C.A. M.S. J.C. R.H. A.L. B.B. A.S.

Age at exam (mo.) 36 & 40 13 27 3 30, 36 & 42 148 1.25 60Visual acuity F&F F&F F&F F&F F&F 20/50, 20/100 F&F 20/25, 20/30Cycloplegic OD +2.50 OU +1.25 OD +0.50 OU +1.50 OD +0.25 OD +1.00 OU +5.00 OU +2.00

refraction(sphericalequivalent)

OS +1.75 OS +0.75 OS +0.50 OS +3.00

Cover test Ortho Ortho Ortho Ortho Right hypertropia Ortho Ortho OrthoEOM N N N N RIO overaction N N NExternal eye Ptosis Ptosis OU Ptosis OU Ptosis Ptosis OD>OS Ptosis OU, N N

exam OD>OS OS>OD latent nystagmusnystagmus OD

Slit lamp anteriorsegment exam

N N N N N N N N

Crystalline lens Clear Clear Clear Clear Clear Clear Clear ClearFundus exam N N N N At 30 mo, normal; at

36 & 42 mo.,bilateral opticatrophy anddysplasia

Bilateral opticnervehypoplasia

N N

*N, normal; OD, right eye; OS, left eye; OU, both eyes; F&F, good fixation and following vision; EOM, extraocular muscle movement; RIO, right inferioroblique muscle.

502 Atchaneeyasakul et al.

During the course of this study, the authors had theopportunity to analyze sterol content in the tissues of astillborn infant of 32 weeks gestation with features ofSLOS. Transabdominal chorionic villus sampling hadbeen performed and karyotype was normal 46,XX. Au-topsy showed flattened small nose, micrognathia, amidline cleft of the soft palate, crumpled ears, bilateralpostaxial polydactyly of the hands, single transversepalmar creases, camptodactyly of the index fingers bi-laterally, and extensive cutaneous syndactyly of thesecond and third toes on both feet. The eyes appearedcollapsed and no detailed autopsy findings were docu-mented initially. External genitalia were those of anormal female. Internal examination demonstrated alarge ventricular septal defect. Kidneys were initiallyidentified but the microscopic sections of presumed kid-neys were consistent with the architecture of the adre-nal gland. Bilateral renal agenesis was suspected. Anormal-appearing uterus and ovaries were identified.Findings in the respiratory, gastrointestinal, hepato-biliary, hematopoietic, and central nervous systemswere unremarkable. Biochemical sterol analysis wasperformed by gas chromatography on ocular tissues in-cluding the retina, retinal pigment epithelium, lens,cornea, sclera, and extraocular muscle to confirm thediagnosis and in an attempt to determine the etiologyof the ophthalmologic abnormalities in SLOS.

RESULTS

The diagnosis of Smith-Lemli-Opitz syndrome wasconfirmed by biochemical analysis of plasma choles-terol and 7-dehydrocholesterol levels in all patients inthis study. All patients were the products of non-consanguineous marriages. The youngest age at thediagnosis of SLOS was 1 week and the oldest age was5 years. Five patients were female and three patientswere male. Two patients (C.A. and A.L.) were the prod-ucts of non-identical twin pregnancy. The twin of A.L.was stillborn, the twin of C.A. is healthy. None of thepatients was born before 36 weeks of gestation andnone of them had a birth weight and length less than

the 5th centile. Of four patients on whom head circum-ference at birth was known, one was microcephalicsince birth and two developed microcephaly later. De-velopmental delay was detected in all but one patientand varied from mild (4 to 6 months behind) to severe(2 years behind). Patient B.B. was only 4 weeks old atthe time of developmental evaluation. Postnatalgrowth retardation was found in 6 patients. PatientJ.C. was only 3 months old at the last examination andgrowth parameters were normal. Patient A.L. was 13years old at the last examination and his growth pa-rameters were all normal, including the developmentof secondary sex characteristics. Karyotype in 4 pa-tients (K.B., M.S., R.H., and B.B.) was normal.

The ophthalmologic findings are summarized inTable II. Patient C.A. had a history of partial nasolac-rimal duct obstruction in the neonatal period, whichresolved by the time of eye examination at age 1 yearold. Six of 8 patients demonstrated blepharoptosis ofmild to moderate degree. Two patients were old enoughfor an evaluation of visual acuity by Snellen chart. Pa-tient A.S. has normal visual acuity. In patient A.L.,visual acuity was decreased in both eyes, the right eyewas 20/50 and the left eye was 20/100. His cycloplegicrefraction demonstrated anisometropia with moderateastigmatism in the left eye. Other abnormal findings inthis patient were horizontal nystagmus with a faceturn towards the null point and bilateral optic nervehypoplasia (Fig. 1). Visual acuity in the other 6 pa-tients was assessed by observing fixation and followingmovements. All patients were able to fix and follow anobject of 2 cm size at 1 meter distance and the resultsof cycloplegic refraction were all normal. None of themdemonstrated amblyopia or strabismus except for pa-tient R.H., who demonstrated right hypertropia fromoveraction of the right inferior oblique muscle. She alsodemonstrated latent nystagmus in the right eye. Slitlamp examination of the anterior segment of the eyesshowed normal cornea, anterior chamber, iris, and lensin all patients. Mittendorf’s dot was detected on theposterior surface of the lens in patient C.A. Abnormalfundus findings were demonstrated in 2 patients in-cluding bilateral optic atrophy and dysplasia in patient

Fig. 1. Patient A.L. Fundus photograph showing bilateral small opticnerve head surrounded by a ring of decreased pigmentation (‘‘double-ring’’)and tortuosity of major retinal vessels.

Fig. 2. Patient R.H. Fundus photograph at age 3.5 years showing opticdiscs that are mildly elevated, swollen, pale, and dysplastic.

RSH Syndrome: Eye Findings 503

R.H. (Fig. 2) and bilateral optic nerve hypoplasia inpatient A.L. In patient R.H., fundus findings were nor-mal at 2.5 years old, but subsequent examination at 3.0and 3.5 years old showed abnormal optic discs.

The results of sterol analysis in the ocular tissues ofthe spontaneously aborted fetus with SLOS comparedto a 3 month-old child who did not have SLOS are re-ported in Table III. Cholesterol concentration was lowin the retinal pigment epithelium, lens, cornea, andsclera of the SLOS patient. We detected very high con-centrations of 7- and 8-dehydrocholesterol in all of theocular tissues from the SLOS patient but these me-tabolites were undetectable in the eye without SLOS.

DISCUSSION

Our patients demonstrated a wide spectrum of SLOSphenotype in terms of developmental delay and growthretardation. Ophthalmologic phenotype also varied.Blepharoptosis, the most common ophthalmologic find-ing in SLOS, was demonstrated in 75% of our patients.The severity of blepharoptosis in 2 patients (K.B. andR.H.) requires subsequent evaluation for early detec-tion of occlusion amblyopia. Congenital cataracts,which had been described in 6 of 52 patients with SLOSin a previous study [Gold and Pfaffenbach, 1975], werenot present in any patients in this study. One patient(C.A.) showed a remnant of the primary vitreous, theso-called Mittendorf’s dot on the posterior lens capsule.This developmental anomaly did not affect visual acu-ity. One patient (R.H.) demonstrated right hypertropiafrom overaction of the right inferior oblique muscle,which is different from convergent strabismus (esotro-pia) noted in the previous literature. Nystagmus hadbeen reported in 3 out of 52 cases in a previous study[Gold and Pfaffenbach, 1975]. In this study, patient(R.H.) has latent nystagmus and patient (A.L.) has con-genital nystagmus. Patient A.L. also had a history ofpatching therapy for anisometropic amblyopia. Hisfundus examination showed bilateral optic nerve hypo-plasia comprising of small optic nerve head surroundedby a ring of decreased pigmentation (‘‘double-ring’’) andtortuosity of major retinal vessels. This finding has notbeen reported previously in SLOS patients. Recently,there was a report of high prevalence of astigmatism in

optic nerve hypoplasia [Zeki, 1990], a finding whichwas also encountered in our patient. Interestingly, thispatient has a mild phenotype of SLOS but demon-strates bilateral optic nerve hypoplasia which repre-sents an intrauterine degenerative phenomenon of theoptic axons. The association between optic nerve hypo-plasia and SLOS requires further study with carefulobservation.

Optic atrophy was reported in 3 of 52 cases withSLOS [Gold and Pfaffenbach, 1975]. We found bilateraloptic atrophy in one patient (R.H.) that appeared to beacquired in nature. The presence of swelling of the op-tic discs may be the prelude to the formation of opticatrophy. This patient also has severe developmentaldelay and growth retardation. Optic atrophy developeddespite a high cholesterol diet. The effect of this findingon the final visual function requires follow up exami-nation.

Finally, this is the first report of the sterol profile ofall ocular tissues in SLOS. Sterol analysis confirmedthe presence of 7- and 8-dehydrocholesterol which nor-mally is not detected. Impaired synthesis of cholesterolwith accumulation of cholesterol precursors in oculartissues may explain some of the ocular abnormalitiesseen in SLOS patients. The mechanism for these ab-normalities may be related to the central role of cho-lesterol in modulating the activity of membrane-boundproteins and membrane fluidity [Cenedella, 1996]. Op-tic atrophy may develop in spite of cholesterol supple-mentation suggesting that dietary cholesterol supple-mentation alone may be ineffective in preventing oph-thalmologic abnormalities in SLOS.

ACKNOWLEDGMENTS

The authors thank Drs. L. Hudgins, R. Pagon, and J.Opitz for patient referrals, Martha Neuringer, Ph.D.who dissected the ocular tissues for analysis, AnthonyD’Agostino, MD who performed the autopsy, Don Lin,MS for sterol analysis, the staff of the GCRC for theirassistance, and families for their participation. Thiswork was supported in part by a Young InvestigatorResearch Grant from the American Academy of Pedi-atrics Section on Genetics and Birth Defects, PublicHealth Service grant 5 M01 RR0033 to the OHSU

TABLE III. Sterol Analysis in Ocular Tissues (Microgram/gram) From a Spontaneously Aborted Fetus With SLOS*

Cholesterol8-dehydro-cholesterol

Di-enesterol

19 nor-5,7,9cholestatriene-

3beta-ol7-dehydro-cholesterol 7-DHC/chol Total

Cholesterol in a3-month-old child†

Retina 6360.1 4593 1413.4 1413.4 2473.3 0.39 16253.6 1552.6(%) (39.1) (28.3) (8.7) (8.7) (15.2)Retinal pigment 484.5 469.6 231.1 263.3 451 0.93 1899.5 1362.5

epithelium (%) (25.5) (24.7) (12.2) (13.9) (23.7)Lens 127.2 259.1 98.9 84.8 188.4 1.48 758.4 703.5(%) (16.8) (34.2) (13) (11.2) (24.8)Cornea 52.7 18 8.3 9.7 20.8 0.40 109.5 148.6(%) (48.1) (16.4) (7.6) (8.9) (19)Sclera 71 63 37.2 14.3 31.5 0.44 217.5 391.8(%) (32.9) (29) (17.1) (6.6) (14.4)Ocular muscle 718.5 231.8 132.1 127.5 294.4 0.41 1503.4(%) (47.8) (15.4) (8.8) (8.5) (19.5)

*The numbers in parentheses are percentage of total sterols.†No other sterols detected.

504 Atchaneeyasakul et al.

GCRC, Research to Prevent Blindness, and The Foun-dation Fighting Blindness. R.D.S. is a junior investiga-tor in the Oregon Child Health Research Center.

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