Macular fibrosis complicating macular pigment deficient maculopathy in Sjögren-Larsson syndrome.

Abstract

Sjögren-Larsson syndrome (SLS) is an autosomal recessive neurocutaneous disorder with a typical juvenile macular dystrophy, characterized by crystalline maculopathy (Willemsen et al. 2000), pseudocystic retinal degeneration and lack of macular pigment (MP) (van der Veen et al. 2010). There is evidence that MP (lutein and zeaxanthin) may be important to prevent macular degeneration (Moeller et al. 2006). Furthermore, lutein intake appeared to suppress the development of choroidal neovascularization (CNV) in a mouse model (Izumi-Nagai et al. 2007). We report bilateral CNV formation in a young adult with SLS. A 26-year-old woman, SLS patient 10 in a previous clinical study (Willemsen et al. 2000), presented with visual loss of her right eye. She was known with bilateral crystalline macular dystrophy since she was 11 years old. Best-corrected visual acuity of her right eye had decreased from 20 of 100 1 year earlier to hand movements at 1 m. A white, prominent lesion was visible in the right macula, without cells and flare in the vitreous or in the aqueous humour. The left eye showed multiple glistening dots in the macula as before. Fluorescein angiography (FA) revealed late leakage of the lesion in the right eye, obviously supplied from a feeder vessel observable in the early phase. Spectral-domain optical coherence tomography (SD-OCT) showed a subretinal mass with vitreous traction. Because of the lack of inflammation signs at any time, the lesion was classified as fibrovascular scar following CNV. Due to the obvious end stage of the disease in the right eye, no therapeutic intervention was planned. At the age of 32 years, the patient presented again because her visual acuity of the left eye had decreased from 20 of 100 to 20 of 400 since 5 weeks. Fluorescein angiography (FA) showed diffuse leakage with a subretinal mass on SD-OCT, suggesting active CNV. The patient was treated with bevacizumab intravitreally for three times. Post-treatment control revealed no more leakage and visual acuity increased to 20 of 160. Fluorescein angiography (FA) and SD-OCT images are depicted in Fig. 1. Patients with SLS bear two important risk factors to develop CNV secondary to their juvenile macular dystrophy. The absence of fatty aldehyde dehydrogenase (FALDH) in SLS can cause cell damage and inflammation due to toxic fatty aldehyde molecules (Rizzo 2007), and the anti-oxidative macular pigment is seriously reduced in SLS (van der Veen et al. 2010). We have reported a significantly lowered macular pigment optical density (MPOD) in SLS patients, with −0.47 versus normal at 1° eccentricity (van der Veen et al. 2010). Therefore, one may assume retinal light transmission to be increased with 53% in SLS patients compared to healthy individuals. The likelihood for phototoxic effects by daylight may thus be assumed considerably increased in SLS patients. Besides direct light toxicity to the retina, disruptions of the retinal pigment epithelium, as described earlier in SLS, may have led to scar formation (van der Veen et al. 2010). Also, the appearance of the CNV with vitreous adhesions is atypical. Even though no signs of retinochoroidal inflammation could be observed in our patient, an inflammatory process leading to a fibrovascular macular scar cannot completely be ruled out. In conclusion, our patient developed CNV in both eyes within a few years at young age, possibly as a consequence of retinal light damage due to lack of macular pigment. Even though this complication has not been reported earlier, one may expect that more SLS patients could develop CNV due to their high retinal risk profile. SLS could serve as a disease model for the development of end-stage macular degeneration if macular pigment is severely reduced.