|Year : 2023 | Volume
| Issue : 2 | Page : 396-398
A rare combination: Bardet–Biedl syndrome with atypical retinitis pigmentosa and optic disc drusen
Gulshan Barwar1, Swapnil M Parchand1, Anil B Gangwe1, Deepshikha Agrawal2
1 Department of Vitreo-Retina Services, MGM Eye Institute, Raipur, Chhattisgarh, India
2 Department of Cornea and Anterior Segment Services, MGM Eye Institute, Raipur, Chhattisgarh, India
|Date of Submission||03-Aug-2022|
|Date of Acceptance||07-Dec-2022|
|Date of Web Publication||28-Apr-2023|
5th Mile, Vidhan Sabha Road, Saddu, MGM Eye Institute, Raipur - 493 111, Chhattisgarh
Source of Support: None, Conflict of Interest: None
A 19-year-old male presented with night blindness and gradual diminution of vision since 5 years. Clinical examination and investigations revealed bilateral atypical retinitis pigmentosa (punctata albescens) with foveal atrophy and optic disc drusen. On general examination, patient had central obesity, post-axial polydactyly and brachydactyly in upper and lower limbs, hypogonadism, cognitive deficit, and speech impairment, which were suggestive of Bardet–Biedl syndrome. This is a rare case of Bardet–Biedl syndrome with atypical retinitis pigmentosa (punctata albescens) and bilateral optic disc drusen.
Keywords: Atypical retinitis pigmentosa, Bardet–Biedl syndrome, optic disc drusen
|How to cite this article:|
Barwar G, Parchand SM, Gangwe AB, Agrawal D. A rare combination: Bardet–Biedl syndrome with atypical retinitis pigmentosa and optic disc drusen. Indian J Ophthalmol Case Rep 2023;3:396-8
|How to cite this URL:|
Barwar G, Parchand SM, Gangwe AB, Agrawal D. A rare combination: Bardet–Biedl syndrome with atypical retinitis pigmentosa and optic disc drusen. Indian J Ophthalmol Case Rep [serial online] 2023 [cited 2023 Jun 2];3:396-8. Available from: https://www.ijoreports.in/text.asp?2023/3/2/396/374913
Bardet–Biedl syndrome (BBS) is a rare autosomal recessive ciliopathy characterized by retinal dystrophy, obesity, post-axial polydactyly, renal dysfunction, learning difficulties, and hypogonadism.
The most common diagnostic handle prompting investigation for BBS is the development of rod–cone dystrophy. Primary loss of rod photoreceptors is followed by later demise of cone photoreceptors. This presents as an atypical retinitis pigmentosa with early macular involvement. Obesity is another major clinical finding, and the incidence is reported to be 89% in the BBS population. Developmental delay, cognitive deficit, and speech deficit are common in BBS, with renal abnormalities being the major cause of morbidity and mortality in BBS.
Rod–cone dystrophy is thought to be a consequence of abnormal trafficking across the defective modified cilia connecting the inner and outer segments of photoreceptors, leading to apoptosis.
Retinitis punctata albescens is a progressive rod–cone dystrophy, with autosomal recessive transmission. The fundus aspect in retinitis punctata albescens presents multiple discrete white spots, especially scattered toward the equator.
Optic disc drusen (ODD) are acellular deposits located in the optic nerve head of up to 2.4% of the population. They may develop as by-products of impaired axonal metabolism in genetically predisposed individuals, in whom a narrow scleral canal is hypothesized to play a role. In children, the ODD are usually uncalcified and buried within the optic nerve head tissue. In these cases, the condition can be difficult to diagnose, as it often resembles a papilledema with optic nerve head swelling caused by raised intracranial pressure. During the teenage years, the ODD progressively become more calcified and probably also larger, which allow them to be visible on ophthalmoscopy.
| Case Report|| |
A 19-year-old male presented with the chief complaint of night blindness and gradual diminution of vision since 5 years, with visual acuity in both eyes being counting fingers (CF) 3 m and <N36 for distance and near, respectively. On general examination, the patient had central obesity [Figure 1]a, post-axial polydactyly, and brachydactyly [Figure 1]b and [Figure 1]c in upper and lower limbs, hypogonadism, cognitive deficit, and speech deficit with body mass index (BMI) of 28.7 (overweight).
Fundus examination of both eyes [Figure 2]a and [Figure 2]b revealed disc pallor with mild elevation of the disc. Arteriovenous ratio was normal. Foveal reflex was dull with foveal atrophy noted clinically. Bilateral scattered hypopigmented spots [Figure 2]c and [Figure 2]d were seen in all retinal quadrants with foveal sparing. Typical hyperpigmented bone spicules were not seen in the mid-periphery.
|Figure 2: (a–d) Fundus photo showing disc pallor with disc edema and dull foveal reflex with foveal atrophy in right (a) and left (b), respectively. Mid-periphery reveals absence of typical hyperpigmented bone spicules, while multiple scattered hypopigmented changes are seen from the vascular arcade extending up till the equator in the right (c) and left (d) eye fundus|
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Spectral domain optical coherence tomography (OCT) of both eyes revealed smooth vitreoretinal interface with normal foveal contour. Retinal layer at macula could be differentiated with foveal atrophy [Figure 3]a and [Figure 3]b in both the eyes.
|Figure 3: (a and b) Spectral domain OCT of right (a) and left (b) eyes reveals normal foveal contour with undifferentiated retinal layer at the macula and foveal atrophy. B-scan ultrasonography demonstrates a highly reflective echogenic dot-like structure over the optic nerve head, corresponding to bilateral optic disc drusen in the right (c) and left (d) eyes, respectively. OCT = optical coherence tomography|
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Ultrasound A-scan revealed a high-amplitude tall spike over the optic nerve head in both eyes, and B-scan ultrasonography demonstrated a highly reflective echogenic dot-like structure over the optic nerve head, corresponding to bilateral ODD [Figure 3]c and [Figure 3]d.
Electroretinogram (ERG) showed no scotopic and photopic response in both eyes.
Patient was advised low vision aid (LVA) for improvement in distance as well as near vision and referred to nephrologist and endocrinologist.
| Discussion|| |
The predominant features of BBS are retinal dystrophy (94%), central obesity (89%), polydactyly (79%), cognitive impairment (66%), hypogonadism (59%), and renal abnormalities (52%), with minor features being neurodevelopmental abnormalities, dysmorphic craniofacial features, anosmia, oral–dental abnormalities, and cardiovascular, gastrointestinal, and endocrine abnormalities.
Retinitis punctata albescens is relatively difficult to diagnose than a typical retinitis pigmentosa due to absence of pigmentary fundus changes in the form of bone spicules.
Prevalence of ODD in the rod–cone dystrophy is 2.95%.; while atypical retinitis pigmentosa rarely presents with ODD.
Literature search revealed few isolated case reports on BBS with atypical retinitis pigmentosa, and atypical retinitis pigmentosa with bilateral ODD. None of the published literature has reported all the above clinical entities, that is, BBS, atypical retinitis pigmentosa, and ODD in a single case report.
Patient and relatives were counseled about the clinical entities, and the patient was referred to nephrologist and endocrinologist for any associated renal or metabolic disorder.
Further molecular genetic examinations are required to be performed in order to establish the gene mutation and to refer the patient for genetic counseling.
Patient has two younger brothers who were also called for ocular examination.
| Conclusion|| |
In summary, to our knowledge, this is the first case report of a rare combination of BBS and atypical retinitis pigmentosa (punctata albescens) with bilateral ODD.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]