Journal of Pediatric Ophthalmology and Strabismus

Optic Nerve Hypoplasia in Chondrodysplasia Punctata

Frank A Billson, MD; Creig S Hoyt, MD

Abstract

Chondrodysplasia punctata was first described in 1914 by Conradi, who called the syndrome, "chondroystropica totalis hypoplastica."1 This syndrome is characterized by stippling of the epiphyseal centers and dysplastic skeletal changes. Recently, six constant features and nine variable ones have been established.2 The constant features of the disease are saddle-nose deformity, hypertelorism, frontal bossing, high-arched palate, short neck, and short stature. The variable signs include rhizomelia, flexion contractures, congenital dislocation of the hip, cataracts, optic atrophy, psychomotor retardation, skin rash, renal anomalies, and congenital heart disease.

The syndrome has been subdivided into two major types: (1) the lethal type; and (2) the milder C on rad i-Hu nermann type.3 The rhizomelic type carries a very poor prognosis and usually leads to death in the first few years of life. There is gross long bone shortening, metaphyseal splaying and epiphyseal stippling of the humeri and femor. This type has a higher frequency of associated cataracts, psychomotor retardation and spasticity. It appears to be transmitted as an autosomal recessive trait

The Conradi-Hu nermann type carries a good prognosis and has a wide variation of associated abnormalities. The shortening of the tubular bones and epiphyseal changes tend to be asymmetric and mild. Patients usually have normal intelligence. Cataracts and skin changes are said to be much less common than in the rhizomelia form. Genetic studies suggest that this form is caused by a dominant mutation.3

Reports of the ocular features of chondrodysplasia punctata have documented cataracts, optic atrophy, posterior embryotoxin, strabismus, nystagmus, and adhesions between iris and cornea in the ring of Schwalbe.4-10 In all but a very few cases of cataracts, these ocular findings have been limited to the rhizomelic form of chondrodysplasia punctata. In this paper we report a case of the more benign Conradi-Hunermann form of chondrodysplasia punctata in which unilateral optic nerve hypoplasia was identified as the only ocular anomaly.

CASE REPORT

J.K., a male, was born on Sept 27, 1963, after a normal gravidity as the second child of healthy parents. At one year of age he was referred to the Royal Children's Hospital, Melbourne, for evaluation of growth retardation. There was no family history of dwarfism.

On examination he was found to have short arms and legs with visable bowing of both tibiae. His feet were large and broad. No contractures or hip abnormalities were noted. The bridge of the nose was flat and he appeared to have mild hypertelorism. His neck was short and he had a high arched palate.

Ophthalmologic examination revealed that the patient had a constant left esotropia of 25-30 ? at near and distance. Both pupils were 4 mm in diameter in ordinary light, but the left pupil revealed a 4+ afferent pupillary defect on the "swinging flashlight" test Examination under anesthesia revealed no abnormalities of the anterior segments or lenses. Optic nerve hypoplasia of the left disc was diagnosed on the basis of an optic nerve head which was approximately 1/2 the normal size. The hypoplastic nerve head was pale with normal development of the retinal vasculature The right fundus was entirely normal.

DISCUSSION

The most common ocular defect reported in association with chondrodysplasia punctata has been cataracts. Bilateral cataracts were present in 17 of 55 cases reviewed by Allansmith and Senz.11 Of the cases reported by Johnson and Oriatti, 33 percent had cataracts.12 Pathologic studies have shown that the cataracts in Chondrodysplasia punctata are usually anterior capsular opacities with no unique identifying histochemical characteristics.9 Perhaps because of the frequent obscuration of the fundus by cataracts, detailed studies of the posterior pole have not been reported in chondrodysplasia punctata. Francois has stated…

Chondrodysplasia punctata was first described in 1914 by Conradi, who called the syndrome, "chondroystropica totalis hypoplastica."1 This syndrome is characterized by stippling of the epiphyseal centers and dysplastic skeletal changes. Recently, six constant features and nine variable ones have been established.2 The constant features of the disease are saddle-nose deformity, hypertelorism, frontal bossing, high-arched palate, short neck, and short stature. The variable signs include rhizomelia, flexion contractures, congenital dislocation of the hip, cataracts, optic atrophy, psychomotor retardation, skin rash, renal anomalies, and congenital heart disease.

The syndrome has been subdivided into two major types: (1) the lethal type; and (2) the milder C on rad i-Hu nermann type.3 The rhizomelic type carries a very poor prognosis and usually leads to death in the first few years of life. There is gross long bone shortening, metaphyseal splaying and epiphyseal stippling of the humeri and femor. This type has a higher frequency of associated cataracts, psychomotor retardation and spasticity. It appears to be transmitted as an autosomal recessive trait

The Conradi-Hu nermann type carries a good prognosis and has a wide variation of associated abnormalities. The shortening of the tubular bones and epiphyseal changes tend to be asymmetric and mild. Patients usually have normal intelligence. Cataracts and skin changes are said to be much less common than in the rhizomelia form. Genetic studies suggest that this form is caused by a dominant mutation.3

Reports of the ocular features of chondrodysplasia punctata have documented cataracts, optic atrophy, posterior embryotoxin, strabismus, nystagmus, and adhesions between iris and cornea in the ring of Schwalbe.4-10 In all but a very few cases of cataracts, these ocular findings have been limited to the rhizomelic form of chondrodysplasia punctata. In this paper we report a case of the more benign Conradi-Hunermann form of chondrodysplasia punctata in which unilateral optic nerve hypoplasia was identified as the only ocular anomaly.

CASE REPORT

J.K., a male, was born on Sept 27, 1963, after a normal gravidity as the second child of healthy parents. At one year of age he was referred to the Royal Children's Hospital, Melbourne, for evaluation of growth retardation. There was no family history of dwarfism.

On examination he was found to have short arms and legs with visable bowing of both tibiae. His feet were large and broad. No contractures or hip abnormalities were noted. The bridge of the nose was flat and he appeared to have mild hypertelorism. His neck was short and he had a high arched palate.

Ophthalmologic examination revealed that the patient had a constant left esotropia of 25-30 ? at near and distance. Both pupils were 4 mm in diameter in ordinary light, but the left pupil revealed a 4+ afferent pupillary defect on the "swinging flashlight" test Examination under anesthesia revealed no abnormalities of the anterior segments or lenses. Optic nerve hypoplasia of the left disc was diagnosed on the basis of an optic nerve head which was approximately 1/2 the normal size. The hypoplastic nerve head was pale with normal development of the retinal vasculature The right fundus was entirely normal.

Fig. 1. X-rays of the lower extremities revealing the typical punctate epiphyseal changes and metaphyseal widening.

Fig. 1. X-rays of the lower extremities revealing the typical punctate epiphyseal changes and metaphyseal widening.

Roentgenograms of the extremities revealed typical findings of chondrodysplasia punctata including irregular calcium deposits of the epiphyses around the large joints, bowing and shortening of the tibiae and bones of the forearm, and fragmentation of the protuberances of the vertebrae. The left optic foramen was extraordinarily reduced in size as viewed on orbital xrays.

Follow-up examinations during the past 12 years have revealed a bright intelligent boy who has excelled in school despite his dwarfism and visual handicap. Visual acuity is 6/6 in the right eye and light perception only in the left The left esotropia has increased to 40 ?. Repeat x-rays have revealed gradual disappearance of the cartilaginous structures of the knees, ankles and vertebral bodies. Severe shortening of the long bones of the extremities persists in addition to the facial features, saddle-nose deformity and hypertelorism.

Fig. 2. Side view of the patient demonstrating saddle nose deformity.

Fig. 2. Side view of the patient demonstrating saddle nose deformity.

Fig. 3. Fundus photo of left eye demonstrating optic nerve hypoplasia. Note that the disc is surrounded by a pale scleral ring (arrow) where normal disc margin should be seen.

Fig. 3. Fundus photo of left eye demonstrating optic nerve hypoplasia. Note that the disc is surrounded by a pale scleral ring (arrow) where normal disc margin should be seen.

DISCUSSION

The most common ocular defect reported in association with chondrodysplasia punctata has been cataracts. Bilateral cataracts were present in 17 of 55 cases reviewed by Allansmith and Senz.11 Of the cases reported by Johnson and Oriatti, 33 percent had cataracts.12 Pathologic studies have shown that the cataracts in Chondrodysplasia punctata are usually anterior capsular opacities with no unique identifying histochemical characteristics.9 Perhaps because of the frequent obscuration of the fundus by cataracts, detailed studies of the posterior pole have not been reported in chondrodysplasia punctata. Francois has stated that optic atrophy may occur in chondrodysplasia punctata,'0 but the authors know of no pathologic study documenting this. In the autopsy case report of a patient with the rhizomelic form of this disorder by Levine et al, the right optic nerve appeared hypoplastic rather than atrophic.9

Our case is clearly that of the CondradiHunermann type as is seen by the long survival of the patient and his development of normal intelligence. The gradual resolution of the punctate changes seen on radiologic studies is compatible only with the benign form of this disorder. The only ocular feature of this case is the unilateral optic nerve hypoplasia (and resultant left esotropia). Clinical recognition of various degrees of severity of optic nerve hypoplasia has become increasingly common in the past several years.13·14 The range of dysfunction may extend from nearly normal visual acuity to bare perception of light Optic nerve hypoplasia may be seen as an isolated unilateral or bilateral defect13*14 in association with central nervous system abnormalities (including agenesis of the corpus callosum and septum pellucidum) and pituitary dwarfism,15 in Down's syndrome,16·17 or as part of a lethal cardiac-renal dysgenesis syndrome.16 Infrequently optic nerve hypoplasia has been reported as a familial trait18

Optic atrophy has often been confused with optic nerve hypoplasia because of the pale scleral ring which often surrounds and blends with hypoplastic optic nerve head.13 The diagnosis of optic nerve atrophy was considered initially in our patient before an adequate examination under anesthesia could be completed. Visual function in those few patients with chondrodysplasia punctata who survive and undergo cataract surgery frequently has been discouraging.19 It has been argued that this may be due to concomitant optic atrophy in these patients. We suggest that many of the cases of suspected optic nerve atrophy reported in association with chondrodysplasia punctata may, in fact, be cases of optic nerve hypoplasia. Thorough clinical examination of the posterior pole may be difficult in these often critically ill young children, many of whom have dense cataracts. Nonetheless, future clinical and pathological studies of the ocular features of chondrodysplasia punctata should address themselves to detailing whether optic nerve hypoplasia and/or optic atrophy is associated with this disorder.

SUMMARY

A case of optic nerve hypoplasia in the Conradi-Hunermann form of chondrodysplasia punctata is reported. This is the first published report of such a case. The authors suggest that optic nerve hypoplasia in chondrodysplasia punctata may be the significant lesion of the optic nerve rather than atrophy as has been previously reported.

REFERENCES

1. Conradi E: Vorzeitges Auftreten von knochen und Eigenartigen Verkalkungskeren bei Chondrodystrophia Fotalis Hypoplastica. J Kinderheilkd 80:86, 1914.

2. Tasker WG, Mastri AR, Gold AP: Chondro· dystrophica calcificans congenita (dysplasia epiphysalis punctata). Am J Dis Child 119:122, 1970.

3. Spranger J, Opitz JM, Bidder U: Heterogeneity of chondrodysplasia punctata. Humangenetik 11:190, 1971.

4. Armaly MF: Ocular involvement in Chondro· dystrophica calcificans congenita punctata. Arch Ophth 57:491, 1957.

5. DeFauw H, Massa J: Cataract congenitale associée a la maladie des epiphyses pontillees. Bull Soc Belge Ophth 131:411, 1962.

6. Hammond A: Dysplasia epiphysialis punctata, with ocular anomalies. Ophthalmologica 165:554, 1972.

7. Hammond A: Dysplasia punctata with ocular anomalies. Brit J Ophth 54:759, 1970.

8. Ryan H: Cataracts of dysplasia epiphysalis punctata. Brit J Ophth 54:197, 1970.

9. Levine R, Snyder A, Sugarman G: Ocular involvement in chondrodysplasia punctata. Am J Ophth 77:851, 1974.

10. Francois J: Syndromes with congenital cataracts. Am J Ophth 52:207. 1961.

11. Allansmith M, Senz E: Chondrodystrophia congenita! punctata (ConradTs disease), review of literature and report Am J Dis Child 100:109, 1960.

12. Josephson BM, Oriatti MD: Chondrodystrophia calcifican congenita. Pediatrics 28:425, 1961.

13. Edwards W, Layden W: Optic nerve hypoplasia. Am J Ophth 70:950, 1970.

14. Walton D, Robb R: Optic nerve hypoplasia: a report of 20 cases. Arch Ophth 84:572, 1970.

15. Hoyt WF, Kaplan SL. Grumbach MM et al: Septc-optic dysplasia and pituitary dwarfism. Lancet 1:893, 1970.

16. Hoyt CS and Billson FA: The spectrum of optic nerve hypoplasia (in preparation).

17. Hackenbruch Y, Meerhoff E, Besio R et al: Familial bilateral optic nerve hypoplasia Am J Ophth 79:314, 1970.

18. van Balen A, Santens P: Chondrodystrophia calcificans congenita. J Ped Ophth 5:151, 1968.

10.3928/0191-3913-19770501-07

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