Sourabh Jandyal, B.Optm

Postgraduate in Optometry (M.Optom), The Sankara Nethralaya Academy, Chennai, India

 

Introduction: Congenital disorder of glycosylation is a group of metabolic disorders with many similar neuro and multi-system involvements ⁽¹⁾. It is said to affect almost all the organs of the body and almost 50-70% of the affected show ophthalmic associations. Following are the commonly known associations:

1. Central hypotonia– presents with depressed level of consciousness and disturbed neuro-muscular co-ordination
2. Microcephaly– reduced frontal-occipital circumference
3. Cerebellar atrophy– deterioration of neurons in cerebellum
4. Delayed developmental milestones
5. Eye anomalies– cataract, corneal opacities, nystagmus, strabismus, progressive visual field loss, hyperopia, impaired night vision, delayed visual maturation and abnormal eye movement etc. are various conditions reported in different case reports and records worldwide. ^(1-3) The most common type PMM2-CDG had been reported in 700 individuals. ⁽⁴⁾

Figure. A. A child with developmental milestones², B. A child with microcephaly² and C. A child with presentable strabismus and delayed developmental milestones¹ microcephaly.

Case report:

A 3-year-old girl was brought to clinic by her parents. Chief complaint was seeing white reflex in her eyes and her bumping into objects while walking around. She was able to recognize the familiar faces.

Birth history: full term baby, birth by normal delivery and negative history of pre/peri/post-natal infections, consanguinity, birth asphyxia or jaundice.

She showed delayed development milestones.

She had already been diagnosed with congenital disorder of glycosylation, central hypotonia and mild microcephaly. An old report results suggested mild cerebellar atrophy.

Clinical evaluation:

Visual acuity:

• No response to Cardiff’s visual acuity chart
• Lea paddles- 0.25cpm (slow responses with both eyes), strong resistance of left eye (OS) occlusion

Objective refraction: post dilation with homatropine

• No glow in right eye (OD)
• +1.00DS (central opacity) in OS

Torch light examination:

• Hirschberg’s test- OD exotropia
• Both eyes Pupils equal, regular and round, reacting to light and accommodation

Slit lamp evaluation – normal extra-ocular features with total cataract in OD and immature cataract in the OS.

Fundus evaluation: no view in OD and normal fundus (hazy view) in OS.

Ultra-sonography showed cataract in OD with grossly seen normal retina and choroid.

Management: The patient was then advised lens aspiration for both eyes considering the right eye first.

Discussion: This is a not so common condition and with each new case reported, the understanding of the associated signs and symptoms widens. It is well known fact that it causes hypotonia which is directly associated with muscle weakness and among the ocular signs, cataract is a commonly known condition. But the lack of knowledge on complete set of signs and symptoms and the understanding on associated systemic conditions make it difficult to get to understand the proper prognosis. Thus, the main research question is whether the stumbling over and bumping over objects is due to the hypotonic condition or just an association to the visual system i.e., a systemic association or due to cataract?

Picture courtesy:

Fig. A and B – De Lonlay, P., Seta, N., Barrot, S., Chabrol, B., Drouin, V., Gabriel, B. M., Journel, H., Kretz, M., Laurent, J., Le Merrer, M., Leroy, A., Pedespan, D., Sarda, P., Villeneuve, N., Schmitz, J., Van Schaftingen, E., Matthijs, G., Jaeken, J., Korner, C., … Cormier-Daire, V. (2001). A broad spectrum of clinical presentations in congenital disorders of glycosylation I: A series of 26 cases. Journal of Medical Genetics, 38(1), 14–19.

Fig. C– Morava, E., Wosik, H. N., Sykut-Cegielska, J., Adamowicz, M., Guillard, M., Wevers, R. A., Lefeber, D. J., & Cruysberg, J. R. M. (2009). Ophthalmological abnormalities in children with congenital disorders of glycosylation type I. British Journal of Ophthalmology, 93(3), 350–354

 

References:

1. Morava, E., Wosik, H. N., Sykut-Cegielska, J., Adamowicz, M., Guillard, M., Wevers, R. A., Lefeber, D. J., & Cruysberg, J. R. M. (2009). Ophthalmological abnormalities in children with congenital disorders of glycosylation type I. British Journal of Ophthalmology, 93(3), 350–354. https://doi.org/10.1136/bjo.2008.145359
2. De Lonlay, P., Seta, N., Barrot, S., Chabrol, B., Drouin, V., Gabriel, B. M., Journel, H., Kretz, M., Laurent, J., Le Merrer, M., Leroy, A., Pedespan, D., Sarda, P., Villeneuve, N., Schmitz, J., Van Schaftingen, E., Matthijs, G., Jaeken, J., Korner, C., … Cormier-Daire, V. (2001). A broad spectrum of clinical presentations in congenital disorders of glycosylation I: A series of 26 cases. Journal of Medical Genetics, 38(1), 14–19. https://doi.org/10.1136/jmg.38.1.14
3. Jensen, H., Kjaergaard, S., Klie, F., & Moller, H. U. (2003). Ophthalmic manifestations of congenital disorder of glycosylation type 1a. Ophthalmic Genetics, 24(2), 81–88. https://doi.org/10.1076/opge.24.2.81.13994
4. Sparks, S. E., & Krasnewich, D. M. (1993). Congenital Disorders of N-Linked Glycosylation and Multiple Pathway Overview. GeneReviews®, 1–23. http://www.ncbi.nlm.nih.gov/pubmed/20301507