Congenital hereditary corneal dystrophy

High measured intraocular pressure in children with recessive congenital hereditary endothelial dystrophy

PURPOSE

To report the phenomenon of high measured intraocular pressure in recessive congenital hereditary endothelial dystrophy.

METHODS

A case series was retrospectively reviewed.

RESULTS

Five infants with significant congenital corneal haze had increased measured intraocular pressure that remained high despite drug treatment and surgery to decrease intraocular pressure. The clinical diagnosis of recessive congenital hereditary endothelial dystrophy without glaucoma was made based on the absence of buphthalmos, a distinct pattern of mosaic corneal haze with significant corneal thickness, and absence of cupping in healthy-appearing optic nerve heads.

CONCLUSION

Intraocular pressure can be falsely elevated in some children with recessive congenital hereditary endothelial dystrophy, leading to confusion with congenital glaucoma.

Coexistent Congenital Hereditary Endothelial Dystrophy and Congenital Glaucoma

PURPOSE

To retrospectively evaluate the coexistence of congenital glaucoma with congenital hereditary endothelial dystrophy.

METHODS

Ten infants presented to our hospital with diffuse corneal edema and bilaterally elevated intraocular pressure (IOP). These patients were diagnosed with congenital glaucoma. All patients underwent trabeculotomy with trabeculectomy for control of IOP. Although IOP was normalized in all patients, corneal edema persisted. These patients underwent penetrating keratoplasty, and the buttons were subjected to histopathologic examination.

RESULTS

The corneal grafts remained clear in all patients. The histopathologic examination of the excised corneal buttons showed diffuse stromal edema, loss of the endothelial cell layer, and thickening of the posterior non-banded portion of the Descemet membrane, suggestive of congenital hereditary endothelial dystrophy.

CONCLUSIONS

Congenital hereditary endothelial dystrophy may coexist with congenital glaucoma. This combination should be suspected where persistent and total corneal opacification fails to resolve after normalization of IOP.

A new, X-linked endothelial corneal dystrophy

PURPOSE

To describe the clinical spectrum, the histopathologic findings obtained from one corneal button, and the genetic mapping of an X-linked endothelial corneal dystrophy (XECD).

DESIGN

Observational case series and experimental study.

METHODS

We examined a total of 60 members of a family with this dystrophy at the slit-lamp. Light and electron microscopic findings of the corneal button were recorded following one male patient's penetrating keratoplasty. A panel of 25 microsatellite markers covering the X chromosome was typed in genomic DNA from 50 family members. The data were analyzed using the ALLEGRO program to obtain two-point and multipoint likelihood of the odds (LOD) scores and to generate haplotypes.

RESULTS

A total of 35 trait carriers were identified in four generations of the family. Nine male patients demonstrated severe corneal opacifications: two congenital corneal cloudings in form of ground glass, milky appearance and seven subepithelial band keratopathies combined with endothelial changes resembling moon craters. Twenty-two female and four male patients disclosed only endothelial alterations resembling moon craters. No instance of male-to-male transmission of the disease was encountered in the family. Light and electron microscopy disclosed focal discontinuities and degeneration of the endothelial cell layer and marked thickening of Descemet's membrane. Multipoint analysis showed linkage with a maximum LOD score of 10.90 between markers DXS8057 and DXS1047.

CONCLUSIONS

To the best of our knowledge, this represents the first fully documented report of X-linked inheritance of an endothelial corneal dystrophy. Late subepithelial band keratopathy is a landmark of XECD. A locus for this corneal dystrophy maps to Xq25.

Homozygosity mapping and linkage analysis demonstrate that autosomal recessive congenital hereditary endothelial dystrophy (CHED) and autosomal dominant CHED are genetically distinct

BACKGROUND

Congenital hereditary endothelial dystrophy (CHED) is a corneal dystrophy characterised by diffuse bilateral corneal clouding resulting in impaired vision. It is inherited in either an autosomal dominant (AD) or autosomal recessive (AR) manner. The AD form of CHED has been mapped to the pericentromeric region of chromosome 20. Another endothelial dystrophy, posterior polymorphous dystrophy (PPM), has been linked to a larger but overlapping region on chromosome 20. A large, Irish, consanguineous family with AR CHED was investigated to determine if there was linkage to this region.

METHODS

The technique of linkage analysis with polymorphic microsatellite markers amplified by polymerase chain reaction (PCR) was used. In addition, a DNA pooling approach to homozygosity mapping was employed to demonstrate the efficiency of this method.

RESULTS

Conventional genetic analysis in addition to a pooled DNA strategy excludes linkage of AR CHED to the AD CHED and larger PPMD loci.

CONCLUSION

This demonstrates that AR CHED is genetically distinct from AD CHED and PPMD.

Congenital hereditary endothelial dystrophy associated with glaucoma

BACKGROUND

Three children, ranging in age from 2 to 6 months, had diffuse and homogeneously opaque corneas, clinically consistent with congenital hereditary endothelial dystrophy. Bilateral elevated intraocular pressure (IOP) was a feature in all three children.

METHODS

Initially, all patients underwent glaucoma surgery to reduce IOP. Subsequently, a penetrating keratoplasty was performed in one eye of each patient to clear the visual axis. The excised corneal button was examined by light microscopy and by transmission and scanning electron microscopy.

RESULTS

Postoperatively, all patients maintained clear corneal grafts. Results of histopathologic examination showed an absence of the endothelial cell layer in all patients. The presence of a variably thick collagenous layer posterior to the anterior banded zone of Descemet's membrane and the absence of endothelial cells were noted on transmission electron microscopy. Scanning electron microscopy confirmed absent, or scanty, and abnormal endothelial cells.

CONCLUSION

The authors describe three patients with a clear association between congenital glaucoma and congenital hereditary endothelial dystrophy. This combination should be suspected where persistent and total corneal opacification fails to resolve after normalization of IOP.

Immuno-electron labelling of matrix components in congenital hereditary endothelial dystrophy

Two corneal buttons were obtained from a patient with congenital hereditary endothelial dystrophy (CHED) at the ages of 2.5 years (right eye) and 14 years (left eye) and were studied by light and electron microscopy including immunogold labelling for collagen types I-V and laminin. The posterior collagenous layer (PCL) of Descemet's membrane contained collagen types I, III-V, and laminin: the latter was also localised to fine-banded and granular material in the posterior non-banded zone (PNBZ). Comparison of the endothelium 2.5 years and 14 years revealed occasional dystrophic changes in the former and extensive dystrophic changes in the latter. The distribution of collagen types I, III and V within the PCL supports previous morphological observations of fibroblast-like change of the endothelium in CHED. Persisting endothelial properties were manifest as positive labelling of type IV collagen and laminin. An excessive amount of laminin found in PNBZ and PCL is another stress-related endothelial reaction.

Congenital hereditary corneal dystrophy associated with esotropia

A family is described in which four of six siblings have congenital hereditary corneal dystrophy associated with esotropia. All cases had been erroneously diagnosed as and operated on for congenital glaucoma. The hereditary aspect of this association is discussed.

Corneal dystrophies. II. Endothelial dystrophies

In general, endothelial dystrophies present three types of clinical manifestations: 1) production of collagenous tissue posterior to Descemet's membrane which appears as cornea guttata, polymorphic excrescences or gray sheets; 2) a disrupted endothelial mosaic in specular reflection; and 3) corneal edema as a reflection of decreased endothelial barrier and pump functions. In this review, the authors discuss three endothelial dystrophies -- Fuchs', posterior polymorphous and congenital hereditary. They describe the clinical, histopathologic and biochemical features, and illustrate each dystrophy with a composite drawing. Dystrophies of the epithelium, Bowman's layer, and stroma were reviewed separately in the September-October 1978 issue of this journal.

Clinical differentiation of recessive congenital hereditary endothelial dystrophy and dominant hereditary endothelial dystrophy

Our review of previously published reports and familial cases revealed that corneal clouding in autosomal recessive congenital hereditary endothelial dystrophy was present at birth or within the neonatal period. Further, corneal changes with time were minimal, nystagmus was often present, and there were no other signs or symptoms. Patients with autosomal dominant endothelial dystrophy usually had clear corneas early in life; corneal opacification was slowly progressive, nystagmus was infrequent, and photophobia, as well as epiphora, may have been the first indications of the dystrophy. As there is usually little or no congenital evidence of the dominant type, "infantile" or "autosomal dominant" hereditary endothelial dystrophy would be more appropriate names for the dominant variant.

Endothelial alterations in congenital corneal dystrophies

We studied the clinical and ultrastructural findings in three different types of congenital endothelial dystrophies: hereditary posterior polymorphous dystrophy, congenital hereditary corneal dystrophy, and a nonhereditary congenital endothelial dystrophy. In the first patient, with hereditary posterior polymorphous dystrophy, a layer of epithelial-like cells was observed adjacent to endothelial cells on the posterior corneal surface. Descemet's membrane displayed a multilaminar pattern and consisted of an anterior, thin (3 mu), PAS-positive layer and a posterior, thicker (25 to 30 mu) zone of abnormal collagen. The second patient, with congenital hereditary endothelial dystrophy, showed a thickened multilaminar Descemet's membrane and scant endothelial cells. In the third patient with nonhereditary congenital endothelial dystrophy, the thickened Descemet's membrane was lined posteriorly by a retrocorneal fibrous membrane. A few degenerated endothelial cells were present. All three cases showed 100- to 110-nm banding posteriorly. In these three clinically distinct entities, electron microscopy was useful in demonstrating the unusual form of endothelial transformation to epithelial-like cells in one patient, in contrast to the more common fibroblast-like metaplasia of endothelial cells seen in the other two patients.