Sjögren–Larsson syndrome: A case that presented with alternating strabismus

Christina Karakosta; Konstantinos Paraskevopoulos; Anastasios Bisoukis; Anna Vernikou; Anna Kokolaki

doi:10.4103/ijo.IJO_1295_22

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CASE REPORT

Year : 2023 | Volume : 3 | Issue : 1 | Page : 112-114

Sjögren–Larsson syndrome: A case that presented with alternating strabismus

Christina Karakosta¹, Konstantinos Paraskevopoulos², Anastasios Bisoukis³, Anna Vernikou², Anna Kokolaki²
¹ Ophthalmology Department, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki; Ophthalmology Department, General Hospital of Athens “Korgialenio -Benakio”, Athens, Greece
² Ophthalmology Department, Penteli General Hospital for Children, Athens, Greece
³ Ophthalmology Department, Athens Public Eye Hospital, Athens, Greece

Date of Submission	25-May-2022
Date of Acceptance	16-Aug-2022
Date of Web Publication	20-Jan-2023

Correspondence Address:
Christina Karakosta
Aristotle University of Thessaloniki, University Campus - 54124, Thessaloniki
Greece

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijo.IJO_1295_22

Abstract

A girl was referred to our clinic for alternating esotropia. The angle of deviation was measured at +45 prism diopters (Δ). The esotropia gradually turned to exotropia over the last 9 years (about −15Δ). Fundoscopy revealed crystalline retinopathy and in combination with the additional clinical findings of ichthyosis, spastic diplegia, and genetic testing, the diagnosis of Sjögren–Larsson syndrome (SLS) was made. The esotropia in this case, which gradually turned to exotropia without any intervention, may reflect the change in the muscle tone and the neurological damage in SLS. Thus, early strabismus surgery should be avoided to prevent its unpredictable outcomes.

Keywords: Esotropia, exotropia, strabismus

How to cite this article:
Karakosta C, Paraskevopoulos K, Bisoukis A, Vernikou A, Kokolaki A. Sjögren–Larsson syndrome: A case that presented with alternating strabismus. Indian J Ophthalmol Case Rep 2023;3:112-4

How to cite this URL:
Karakosta C, Paraskevopoulos K, Bisoukis A, Vernikou A, Kokolaki A. Sjögren–Larsson syndrome: A case that presented with alternating strabismus. Indian J Ophthalmol Case Rep [serial online] 2023 [cited 2023 Feb 1];3:112-4. Available from: https://www.ijoreports.in/text.asp?2023/3/1/112/368131

Sjögren–Larsson syndrome (SLS) is a rare autosomal recessive neurocutaneous disorder characterized by ichthyosis, intellectual disability, and spastic diplegia or tetraplegia.^[1],[2] SLS is caused by bi-allelic mutations in the ALDH3A2, which result in a deficiency of an enzyme, fatty aldehyde dehydrogenase (FALDH).^[3] FALDH has a key role in the oxidation of medium and long-chain aliphatic aldehydes, formed by fatty alcohol, phytanic acid, ether glycerolipids, and sphingolipids.^[1],[3] In FALDH deficiency, long-chain fatty alcohols accumulate and disrupt cell membranes, causing dysfunction of the skin and the white matter of the brain.^[1],[4],[5] The diagnosis of SLS is based on clinical presentation and genetic testing, demonstrating mutations in the ALDH3A2.^[1]

Case Report

A 2-year-old girl was referred to our clinic for alternating esotropia. Her birth was at full term from an uneventful pregnancy. The girl was not able to talk or walk and was regularly examined by a neurologist. The deviation was measured at +45 prism diopters (Δ). The measurement of the refractive error was done 30 minutes after cycloplegia with the instillation of cyclopentolate hydrochloride 1% ophthalmic solution three times at 5-minute intervals. The cycloplegic refraction was +0.25 − 1.75 × 15 in the right eye (OD) and +0.75 − 1.00 × 140 in the left eye (OS). The deviation did not change following the optical correction of the refractive error. The +3.00D test was performed as well to exclude accommodative esotropia. The test was performed comparing the magnitudes of esotropia near with and without +3.00D lenses being worn, and in the present case, the magnitude of the esotropia did not change at all.

Fundoscopy was normal. Alternating occlusion was decided as the primary treatment. Due to the general physical condition of the girl, the parents decided not to proceed with the corrective strabismus surgery, as suggested. The girl was regularly reexamined for 4 years at our department, but due to lack of cooperation, visual acuity could not be evaluated. Nystagmus was present as well. In the last examination, esotropia was +30Δ [Figure 1]a with her corrective glasses, and the visual acuity was approximately 20/50 in OD and 20/40 in OS due to lack of cooperation. Parents admitted that occlusion was not performed at home. The girl was lost to follow-up and re-presented 9 years later with exotropia of − 15Δ [Figure 1]b, and the best-corrected visual acuity (BCVA) was approximately 20/50 in OD and 20/40 in OS due to lack of cooperation. Fundoscopy revealed crystalline retinopathy [Figure 2]. Optical coherence tomography (OCT) demonstrated macular crystals in the inner retinal layers [Figure 3]. The diagnosis of SLS was made based on genetic testing in combination with the additional clinical findings of ichthyosis [Figure 1]c, mental retardation, and spastic diplegia. In the last visit, better cooperation of the patient revealed that BCVA was 20/32 in both eyes.

Figure 1: (a) Esotropia in early childhood. (b) Exotropia 9 years later. (c) Photography of the patient's neck demonstrating ichthyosis

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Figure 2: (a) Fundus photography of the right eye demonstrating crystalline maculopathy. (b) Fundus photography of the left eye demonstrating the crystalline maculopathy

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Figure 3: (a and b) Optical coherence tomography of OD demonstrating macular crystals in the inner retinal layers

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Discussion

SLS is a rare syndrome with an estimated prevalence of 1:200,000 to 1:300,000, whereas this prevalence is 16 times higher in northern Sweden.^[3] The extraocular features include ichthyosis and neurologic disorders.^[6] The ophthalmic features include photophobia, mild reduced visual acuity, retinal thinning, cystic macular degeneration, retinal pigment epithelium atrophy, and deficiency of macular pigment.^[2],[7],[8] The most characteristic ophthalmic feature is macular dystrophy with crystalline inclusions (“glistening white dots”).^[7] Crystalline maculopathy in SLS is thought to be the result of the accumulation of fatty aldehydes and alcohols, which cause changes in cell membrane functions.^[7],[9] Crystalline maculopathy in more advanced stages may be characterized by atrophic changes in the RPE and lipofuscin deposits. OCT may reveal those macular crystals located in the inner nuclear and outer plexiform layers and rarely in the ganglion cell and inner plexiform layers. Cystic foveal cavitation linked to foveal atrophy, ellipsoid zone disruption, and subretinal deposits, probably created by lipofuscin pigment, may also be seen in OCT.^[10] Strabismus in SLS has been reported,^[11] but to the best of authors' knowledge, this is the first report of SLS presented with esotropia, which several years later turned to exotropia without any intervention. This change in deviation may reflect the change in the muscle tone and the neurological damage in SLS.

Conclusion

In conclusion, SLS is a rare autosomal recessive neurocutaneous disorder caused by a deficiency of FALDH. The most characteristic ophthalmic feature of SLS is crystalline macular dystrophy. Strabismus should always be excluded to prevent amblyopia in cases with already reduced visual acuity, and long-term consultation is necessary. Early strabismus surgery should be avoided in SLS to prevent its unpredictable outcomes in the future.

Research ethics and patient consent

The patient and her parents consented in writing to participate in a study, in the course of which the images included in this report were taken. This report does not contain any identifying information. The study was conducted according to the World Medical Association and the Declaration of Helsinki.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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