A case of ocular ochronosis and chronic open-angle glaucoma: merely coincidental?

Alkaptonuria: a rare disease with multiorgan manifestation and a long-awaited diagnosis

Alkaptonuria is a rare inherited disease resulting from a genetic variant leading to homogentisic acid accumulation in body tissues, causing a broad spectrum of symptoms. Our case involves a Caucasian male diagnosed in his 70s, who shares a constellation of symptoms and the diagnosis with his monozygotic twin brother. The symptoms include early-onset arthropathy, tendinopathy, osteopenia, discolouration of the auricular regions and fingers, scleral discolouration, secondary glaucoma, proteinuria, calcification of the mitral valve and black urethral and prostate stones. Additionally, the patient suffers from chronic cough, polyneuropathy and corpus cysts in the thoracic spine have been found. This case highlights the importance of holistic assessments, recognition of familial symptom patterns and early identification of key clinical indicators for rare disease diagnosis. It also underscores the challenge of differentiating rare symptomatic manifestations from those unrelated to alkaptonuria.

Pseudofilariasis, a Presenting Sign of Alkaptonuria

PURPOSE

To report the association of Pseudofilariasis as a presenting sign of Alkaptonuria.

METHOD

Case Report.

RESULTS

A 49-year-old Indian man was referred because of wormlike objects in his left conjunctiva. Ocular and family history was non-contributory. He had not been to India in 15 years. Past medical history revealed hypertension, hypercholesterolemia, arthritis, and a myocardial infarct. He had undergone two stents, bilateral Achilles tendon repairs and bilateral knee replacements. ROS showed longstanding back stiffness and pain. On ocular examination the vision was 20/25 in each eye and positive findings were in the left eye bulbar conjunctival which showed stationary black vermiform (filarial in appearance) foreign bodies along with 2 small corneal limbal pigmented deposits. Conjunctival biopsy showed dilated lymph channels with interstitial proteinaceous material of a light brown color consistent with Ochronotic pigment; hence diagnostic of Alkaptonuria.

CONCLUSIONS

Pseudofilariasis may be a presenting sign of Alkaptonuria and occur years before a clinical diagnosis is made. Filariasis is always involves white worms and never black. Knowing the ophthalmic signs of this rare disease may lead to an accurate diagnosis earlier thusly avoiding unnecessary tests and examinations.

Descemet's membrane folds in ochronosis: a case report

Background

We present this report of a new ophthalmic finding in a patient with ochronosis.

Case presentation

An 85-year-old Caucasian male patient with bilateral dark temporal and nasal pigmentation of conjunctiva and sclera was referred to our hospital owing to low visual acuity. On biomicroscopic examination, bilateral horizontal Descemet’s membrane folds were observed. Corneal tomography revealed irregular and asymmetric “against-the-rule” astigmatism in both eyes. Anterior segment optical coherence tomography demonstrated numerous central Descemet’s without edema or other corneal structure alterations.

Conclusion

This is the first report of Descemet’s membrane folds in ochronosis. These corneal findings suggest that the accumulation of homogentisic acid in the sclera leads to thickening and stiffness of this region. These alterations could remarkably decrease visual acuity owing to topographic corneal curvature alterations, especially in elderly patients.

Association of alkaptonuria and low dose nitisinone therapy with cataract formation in a large cohort of patients

Homogentisic acid (HGA) lowering, disease modifying off-label nitisinone therapy has been used in the United Kingdom National Alkaptonuria Centre (NAC) since 2012. This study evaluated the serendipitous observation of cataract in a large cohort of patients with the very rare disease alkaptonuria (AKU), over a 5-year period. Patients with AKU who attended the NAC since 2012. Standard physical examination and ocular assessment, including photographs of the crystalline lens were taken before commencement of nitisinone 2 mg daily and annually over 5 years. Photographs were randomised and graded by two independent observers using the WHO cataract classification. AKU patients who did not receive nitisinone were included as a control group. HGA was measured on acidified 24 h urine (u-HGA24) and HGA and tyrosine in fasting acidified serum samples (sHGA, sTYR) at each visit. Patients without suitable lens images were excluded. Cataract (mean grade 1) was noted at baseline in 47 out of 62 (76%) with a mean (SD) age of 44 (14) years. In nitisinone-treated patients, there were significant increases in the mean grade of nuclear (0.18, p < 0.01) and cortical (0.38, p < 0.01) lens opacities over the mean duration of 4.93 years of the study. Worsening of the nuclear cataract and cortical lens opacities by at least 1 grade was noted in 14 out of 46 (30%) and 11 out of 46 (24%) patients, respectively. There is an increased prevalence and progression of cataract in AKU and a possible association of nitisinone with cataract progression.

Glaucoma With Alkaptonuria as a Result of Pigment Accumulation

PURPOSE

To report a case of alkaptonuria (AKU) in a patient with bilateral conjunctival and scleral black colorization who was diagnosed with glaucoma thereafter.

METHODS

This is a single case report.

RESULTS

A 67-year-old male patient with bilateral black colorization of conjunctiva and sclera was referred to our hospital. In the biomicroscopic examination, globular dark pigmentation was observed in the conjunctiva, sclera, and limbal cornea. The patient was diagnosed with a nuclear cataract in both eyes. He also had gray skin pigmentation at his nose and paranasal area. Corneal topography examination revealed irregular astigmatism. Intraocular pressure values were 29 and 31 mm Hg, in the right and left eye, respectively, with Goldmann applanation tonometry. The diagnosis of AKU was made after pathologic assessment of conjunctival biopsy by the internal medicine department.

CONCLUSIONS

AKU is characterized by the accumulation of homogentisic acid in the connective tissues of many organs including the eye. Patients should be carefully examined in ophthalmology clinics in order to not miss systemic diagnoses. It should be kept in mind that AKU may cause iridocorneal angle pigmentation, which leads to glaucoma, and patients should be treated with proper medication when presenting with elevated intraocular pressure values.

On the ocular findings in ochronosis: a systematic review of literature

BACKGROUND

Ochronosis/Alkaptonuria is a tyrosine metabolism disorder where accumulation of homogentisic acid, in eye, skin, cartilage and several other connective tissues leads to a black pigmentation of the affected tissues. It is autosomal-recessive inherited in men with a frequency of 1-9/1,000,000. While it is clear that pigment deposits lead to joint destruction, renal stone formation and cardiac valvulopathy respectively, the significance of ocular findings is still unclear. We therefore aim to evaluate the frequency and clinical significance of ocular findings in ochronosis and discuss possible therapeutic options.

METHODS

Systematic review of literature via Medline and Web of Science. Only case reports in English, German, French, Spanish or Italian documenting detailed ophthalmologic examination were included.

RESULTS

Our search revealed 36 case reports including 40 patients. Average age at the onset of ocular signs was 40.6 years. The most frequent sign was symmetric brown sclera pigmentation present in 82.5 percent of the patients. "Oil-drops", brown pigment spots in the limbus are generally considered pathognomonic but were a little less frequent (75 percent). Vermiform pigment deposits at the level of the conjunctiva or increased conjunctival vessel diameter is also frequent. We found an increased incidence of central vein occlusion and elevated intraocular pressure going along with chamber angle hyperpigmentation. Another condition observed twice is rapid progressive astigmatism attributable to corneoscleral pigment accumulation.

CONCLUSION

Our observations suggest that ocular findings are of double relevance. First, characteristic ocular findings can anticipate the time of diagnosis and second, ocular findings may complicate to various conditions putting sight at risk. Opthalmologists and general physicians should be aware of both. Therapeutic options include protein restriction, administration of high dose vitamin C or nitisonone. Evidence for all of them is limited.

[A 69-year-old patient with brown-black pigmentation of the sclera]

In a 69-year-old man with ochronosis, circumscribed brown-black scleral spots with injection of conjunctival vessels and some small pigmentations of the peripheral superficial cornea occurred. Ochronosis is an autosomal recessive chronic disease, whereby early detection of cardiac valvular defects and arthritis is important particularly in patients who are older than 40 years.

Endogenous ochronosis: case report and a systematic review of the literature

BACKGROUND

Endogenous ochronosis (EO) is a rare autosomal recessive disorder due to accumulation of oxidized and polymerized forms of homogentisic acid (HGA) in connective tissues, giving them a deep dark blue pigmentation.

AIM

Through a new Tunisian case of EO and a review of the literature, we aimed to define the epidemioclinical features of EO, its diagnostic criteria, and evolution.

METHODS

Three hundred and forty patients were enrolled through 54 articles and four abstracts.

CASE REPORT

A 35-year-old woman, born in consanguineous parents, presented with blue-grey patches of fingernails, first interdigital spaces, and ears with brown conjunctival pigmentation. Urine specimen turned dark on standing overnight. The diagnosis of EO was confirmed by urinary high levels of HGA. Investigations revealed radiologic signs of ochronotic arthropathy.

REVIEW OF THE LITERATURE

EO is ubiquitary. Its prevalence was estimated at almost 6.5 cases/year. The mean age at diagnosis was 55.9 years (M/F: 1.85). Onset symptoms mainly consisted in cutaneous signs. Ochronotic arthropathy was the most frequently reported manifestation. Treatment was mainly symptomatic.

DISCUSSION

EO is often revealed in adulthood mainly after the fourth decade. Urinary darkening is the first sign of the disease but is rarely reported as an onset sign. Skin signs are the alerting features. Ochronotic arthropathy is insidious but may be debilitating. No specific medical treatment of EO is available.

CONCLUSION

Cutaneous manifestations are the hallmarks of OE. As vital organ involvement has been reported, close monitoring and continuous surveillance is warranted.