Secondary Logo

Journal Logo

Brief Reports

Familial calcific band-shaped keratopathy

Report of two new cases with early recurrence

Arora, Ritu MD; Shroff, Daraius MS; Kapoor, Seema MD; Nigam, Sonu MD; Narula, Ritesh MBBS; Chauhan, Deepender MS; Jain, Priyanka MS

Author Information
Indian Journal of Ophthalmology: Jan–Feb 2007 - Volume 55 - Issue 1 - p 55-57
doi: 10.4103/0301-4738.29496
  • Open

Abstract

Familial calcific band-shaped keratopathy (BSK) is a rare entity which occurs in apparently normal eyes and is not associated with any systemic metabolic abnormality.1 It has been reported in the English literature in only one other report.2 We describe the clinical and histopathological findings in two siblings of a consanguineous marriage with primary calcific BSK.

Case Report

A four-year-old male child, presented with history of diminution of vision and opacification of the cornea of both eyes over the past six months. There was no history of trauma, red eyes, long-term use of topical or systemic drugs. No history of joint pain, lethargy or muscle weakness could be elicited. The birth and developmental history was normal. The child's parents were first cousins. There was no similar history in any of the family members, up to the third generation. On slit-lamp examination both eyes showed dense, sub-epithelial, white deposits in a band-like configuration with a typical swiss-cheese pattern, sparing the limbus and also involving the anterior stroma in the right eye [Fig. 1A]. Visual acuity (VA) was 20/400 (counting fingers (CF) at 3 m) in right eye and 20/300 (CF at 4 m) in left eye. Rest of the ocular examination was unremarkable.

Figure 1A
Figure 1A:
Calcific band-shaped keratopathy (BSK) in right eye of the younger male sibling. Note the dense calcific deposits with typical Swiss cheese configuration
Figure 1B
Figure 1B:
Calcific band-shaped keratopathy in right eye of the older female sibling. Characteristic calcific deposits are seen sparing the limbus. Note that the severity of the disease is less than that seen in the male sibling in Figure 1A
Figure 1C
Figure 1C:
Clear cornea is seen in the immediate postoperative period in the right eye of the female sibling
Figure 1D
Figure 1D:
Recurrence of BSK in the right eye of the female sibling at four weeks, with discrete calcific patches in a band-shaped configuration

A detailed systemic evaluation did not reveal any abnormality. Serum calcium, serum phosphate, blood urea, serum creatinine, alkaline phosphatase and parathyroid hormone (PTH) were normal, as were the electrolytes. Routine hemogram was unremarkable. Urine aminoacidogram showed a normal pattern. Tubular reabsorption of phosphates (TRP) was normal. Urinary phosphate, creatinine and calcium excretion were normal. The chest X-ray and detailed skeletal survey were unremarkable. Ultrasonography of the kidneys was normal.

The child underwent disodium ethylenediamine-tetraacetate (EDTA) (40 mg/ml) chelation under general anesthesia. The epithelium overlying the calcium deposits was removed with a blade and a cellular sponge soaked in the EDTA solution was rubbed against the calcium deposits for 30 min. There was slow dissolution of calcium and complete clearance of calcium from the involved layers in the left eye.

Due to greater density and depth of calcium deposits in the right eye complete chelation was not possible and a superficial keratectomy was resorted to. Postoperatively the right cornea showed some surface irregularity due to keratectomy while left eye was relatively smooth. The VA was 20/240 (CF at 5 m) in right eye and 20/120 in the left eye. At the four-week follow-up patchy epithelial regrowth with calcification in both eyes, with severe recurrence of the band keratopathy was noted. The VA of the right eye dropped to 20/600 (CF 2 m) and the left eye to 20/240 (CF 5 m).

Formalin-fixed, paraffin-embedded, 3 mm thick sections were obtained. On hematoxylin-eosin (H and E) stain dense linear extra-cellular sub-epithelial deposition of a basophilic granular substance suggestive of calcium was seen [Fig. 2].

Figure 2
Figure 2:
Histopathology of the keratectomy specimen of the right eye of the male sibling shows dense extracellular sub-epithelial basophilic granular calcium deposits in a linear pattern (arrows), as well as areas of surgical epithelial debridement (arrow head) (H&E, 400x). The deposits stained positive with von Kossa stain for calcium and were negative with van Geison stain for elastin. No intracellular calcification is seen. No inflammatory cells can be seen around these calcium deposits

Another six-year-old female sibling complained of a decrease in VA and opacification of cornea over past four months. The cornea also showed typical band-like deposits with swiss-cheese pattern of calcification [Fig. 1B]. However, the corneal involvement was less severe, consequently the VA was better than that of the younger sibling (right eye 20/80 and left eye 20/120). The rest of the ocular examination was unremarkable. A similar complete systemic workup of this child did not show any abnormality.

EDTA chelation was carried out and postoperatively corneal clarity improved markedly [Fig. 1C] and a VA of 20/40 was achieved in both eyes. However, at four weeks this patient also showed recurrence of disease with small discrete calcific patches in the band-shaped configuration [Fig. 1D].

Discussion

The two major types of BSK are the calcific type and the spheroidal type. Calcific BSK generally occurs secondary to chronic ocular disease or abnormal calcium or phosphorus metabolism.

In cases with calcific BSK secondary to a local disease, the calcium deposits are extracellularly located in the epithelial basement membrane, Bowman's layer and superficial stroma.3

Systemic disorders including hyperparathyroidism, hypophosphatasia and fanconi syndrome have been implicated as the cause of calcific BSK. Calcium deposits in abnormal systemic metabolism differ from those of chronic ocular disease as they are generally intracellular.3 The calcium deposits in our case were present extracellularly in a linear configuration, similar to those seen in chronically inflamed eyes.

Familial BSK is the rarest variety of BSK. Previously reported cases of primary calcific keratopathy of familial origin are depicted in Table 1. A few reports of familial spheroidal BSK are present in the literature.456

Table 1
Table 1:
Previously reported cases of familial calcific band-shaped keratopathy

The only report of familial calcific BSK in the English literature (on a MEDLINE search) was by Ticho et al. in two siblings.2 The clinical description and photographs indicate a less severe manifestation of the disease than in our cases. No recurrence of the disease was reported. The siblings of familial BSK seen by us had a more severe manifestation in the younger child and recurrence was noted as early as four weeks. In a study on the effectiveness of EDTA chelation in 65 eyes of 54 patients with calcific BSK, Najjar et al.7 reported the mean time for recurrence to be 17.7 years.

Band-shaped keratopathy presenting in first-order relations without an obvious etiology merits a complete systemic and ophthalmic workup before it can be labeled as familial.

To date eight genetic loci have been identified to which corneal dystrophies have been linked.8 The only gene mapped in band keratopathy has been in association with proximal renal tubular acidosis which is the human NBC1 (sodium-bicarbonate co-transporter one) gene, mutations of which result in a syndrome with a severe ocular and renal phenotype (band keratopathy, cataracts and proximal renal tubular acidosis).9 As the parents of these children are first cousins, it is very likely that this represents an autosomal recessive condition. The genetic defect behind this condition merits further research. Patients with familial BSK could be considered poor prognosis cases for treatment with EDTA due to early postoperative recurrence of the disease.12

1. Duke-Elder S, Leigh AGDuke-Elder S. Diseases of the outer eye System of Ophthalmology. 1965 London Kimpton:898–900
2. Ticho U, Lahav M, Ivry M. Familial band-shaped keratopathy J Pediatr Ophthalmol Strabismus. 1979;16:183–5
3. Waring GO 3rd, Mbekeani JNLeibowitz HM, Waring GO 3rd. Corneal degenerations Corneal disorders- Clinical diagnosis and management. 1998 Philadelphia WB Saunders Company:303–13
4. Cohen KL, Bouldin TW. Familial, band-shaped, spheroidal keratopathy histopathology in ethnic Chinese siblings Cornea. 2002;21:774–7
5. Meisler DM, Tabbara KF, Wood IS, Alvarado JA, Biswell R. Familial band-shaped nodular keratopathy Ophthalmology. 1985;92:217–22
6. Kloucek F. Familial band-shaped keratopathy and spheroidal degeneration. Clinical and electron microscopic study Albrecht Von Graefes Arch Klin Exp Ophthalmol. 1977;205:47–59
7. Najjar DM, Cohen EJ, Rapuano CJ, Laibson PR. EDTA chelation for calcific band keratopathy: Results and long-term follow-up Am J Ophthalmol. 2004;137:1056–64
8. Vincent AL, Patel DV, McGhee CN. Inherited corneal disease: The evolving molecular, genetic and imaging revolution Clin Exp Ophthalmol. 2005;33:303–16
9. Bok D, Schibler MJ, Pushkin A, Sassani P, Abuladze N, Naser Z, et al Immunolocalization of electrogenic sodium-bicarbonate cotransporters pNBC1 and kNBC1 in the rat eye Am J Physiol Renal Physiol. 2001;281:F920–35
10. Fuchs A. Ueber primaere guertelfoermige Hornhauttruebung Klin Mbl Augenheilk. 1939;103:300–9
    11. Streiff EB, Zwahlen P. Une famille avec degenerescence en bandelette de la cornee Ophthalmologica. 1946;3:129–34
    12. Glees M. Familial occurrence of primary fascicular degeneration of the cornea Klin Monatsblatter Augenheilkd Augenarztl Fortbild. 1950;116:185–7
    Keywords:

    Band keratopathy; congenital anomalies; cornea; ethylenediamine-tetraacetate chelation; histopathology

    © 2007 Indian Journal of Ophthalmology | Published by Wolters Kluwer – Medknow