Abstract
Optic nerve hypoplasia can be associated with other central nervous system malformations. When associated with the absence of the septum pellucidum or thinning of corpus callosum and pituitary hypoplasia, it is termed septo-optic dysplasia.
Pachygyria is a rare congenital disorder characterized by a defect in migration of cerebral neurons resulting in failure of cortical gyri to develop.
We report a case of a young learning-disabled male presenting with decreased vision, nystagmus, esotropia,, and seizures since childhood. Fundoscopy revealed bilateral optic nerve hypoplasia. Growth hormone levels were reduced. Magnetic resonance imaging revealed thinned optic nerves, optic chiasma and pituitary infundibulum, absent septum pellucidum, box-shaped ventricles and right frontal cortical thickening with few and broad gyro.
This case report highlights a rare case of septo-optic dysplasia with pachygyria.
It also emphasizes that every patient with optic nerve hypoplasia should have an endocrinal and neurological evaluation and neuro-radiographic imaging for associated abnormalities.
Introduction:
Septo-optic dysplasia also known as deMorsier syndrome is a rare congenital anomaly characterized by optic nerve hypoplasia, absence of septum pellucidum or corpus callosum and pituitary hypoplasia. Its prevalence is 1:10,000. More than one third of these patients present with cerebral malformations.
[1] Pachygyria is a rare congenital disorder characterized by a defect in the migration of cerebral neurons resulting in failure of cortical gyri to develop. Thus, the gyri are relatively few and unusually broad. Its prevalence is 1:90,000. The causes for both are genetic or environmental factors like vascular insult and infections during the third and fourth month of gestation.
[2] Maternal ingestion of anticonvulsants, quinine, or alcohol during pregnancy predisposes to septo-optic dysplasia. [3]
Case Report
A 30-year-old learning-disabled male, born of full-term normal vaginal delivery, of non-consanguineous parents presented to us with diminution of vision in both eyes since childhood. There was no history of young maternal age, maternal infections, or maternal drug consumption of anti-depressants, anti-fungals, anti-emetics, or quinine in the ante-natal period. Three of his older siblings were normal. He had delayed developmental milestones in neck holding, sitting, standing, and walking and was suffering from generalized tonic-clonic convulsions since the age of 10 years and was on anti-epileptic treatment tablet carbamazepine 400 mg twice a day.
On examination, the patient had a height of 140 centimeters. Systemic and genital examination was normal. Ocular examination revealed horizontal jerky nystagmus and sluggishly reacting pupils in both eyes and esotropia 30 prism diopters in the left eye. Visual acuity was 10/200 in right and 20/200 in left eye. Fundoscopy showed small, pale optic discs in both eyes [Figure 1]. Visual fields by automated perimetry showed peripheral constriction in both eyes. Color vision testing was normal in both eyes.
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Figure 1: Fundus photograph showing small hypoplastic discs in both eyes
MRI of the brain and orbit revealed thin optic nerves, optic chiasm and pituitary infundibulum, absent septum pellucidum giving typical box-like appearance to the frontal horns of the lateral ventricle [Figure 2], [Figure 3], [Figure 4]. The right frontal cortex was thickened with few broad gyri as compared to the left side which was typical of pachygyria [Figure 5] and [Figure 6].
Figure 2: T2W axial section showing thin optic nerves bilaterally (arrows)
Figure 3: T1W sagittal section showing thin optic chiasm and pituitary infundibulum (arrow)
Figure 4: T2W coronal section showing absent septum pellucidum with box-like appearance of frontal horns of the lateral ventricle (arrow)
{Figure 5}
Figure 6: T1W axial section showing right frontal cortical thickening with few broad gyri (black arrow) and absent septum pellucidum
Growth hormone levels were reduced to 1.2 ng/ml (normal value of >3 ng/ml) after insulin tolerance test. Thyroid hormone levels were normal. Urine analysis, blood sugar level, and serum electrolytes were normal.
Discussion
Optic nerve hypoplasia is non-progressive and characterized by reduced number of ganglion cell axons in the optic nerve. The optic disc is pale and smaller in size, as in our case. The ocular features of nystagmus, strabismus, amblyopia, and visual field defects were noted in our patient. A surrounding peripapillary halo giving rise to the double ring sign, significant cupping, a thin nerve fibre layer, retinal tortuosity, reduced ratio of the disc diameter to disc macula distance to less than 0.35 may also be seen. [4] Pituitary hypoplasia most commonly presents with a growth hormone deficiency causing impaired growth, developmental delay and short stature (pituitary dwarfism) as in our case, while hypoglycemia, hyponatremia, abnormal sexual development, and cerebral palsy are other endocrinal features.
Most cases of septo-optic dysplasia are associated with young maternal age, are sporadic, or autosomal recessive and thus the recurrence risk in consanguineous families, is one in four while in the absence of family history, it is less than 1%. [5] The amblyopia is treated with occlusion therapy and the hypopituitarism with appropriate hormone replacement. Both these modalities could not be offered to our case as he presented to us at a later age.
Septo-optic dysplasia is commonly associated with cerebral anomalies like schizencephaly in 50% of cases. [6] But its association with pachygyria is rare. Carman reported the association of septo-optic dysplasia with pachygyria, schizencephaly,, and diabetes insipidus. [7] Septo-optic dysplasia may be associated with olfactory tract hypoplasia [8] or other cortical dysplasias. [9]
Normally, the brain cells begin to develop in the periventricular region (germinal matrix) and then migrate from medial to lateral during the third and fourth month of gestation, to form the cerebral cortex. Any insult, vascular insufficiency, or infections during this stage causes a defective cortical formation. [10] Pachygyria presents with seizures, developmental delay, and mental retardation, as in our case. Motor deficits can occur. The treatment is supportive and symptomatic in the form of anti-epileptic treatment.
This case report highlights a rare case of septo-optic dysplasia with pachygyria. It also emphasizes that every patient with optic nerve hypoplasia should have an endocrinal and neurological evaluation and neuro-radiographic imaging for associated abnormalities.
References
1. Morishima A, Aranoff GS. Syndrome of septo-optic-pituitary dysplasia: The clinical spectrum. Brain Dev 1986;8:233-9. Back to cited text no. 1
2. Stevens CA, Dobyns WB. Septo-optic dysplasia and amniotic bands: Further evidence for a vascular pathogenesis. Am J Med Genet A 2004;125A:12-6. Back to cited text no. 2
3. Webb EA, Dattani MT. Septo-optic dysplasia. Eur J Hum Genet 2010;18:393-7. Back to cited text no. 3
4. Nayak V, Bhat KR. Septo-optic dysplasia (case report). Indian J Ophthalmol 1991;39:186-7. Back to cited text no. 4
[PUBMED] Medknow Journal
5. Kelberman D, Dattani MT. Genetics of septo-optic dysplasia. Pituitary 2007;10:393-407. Back to cited text no. 5
6. Rajderkar D, Phatak SV, Kolwadkar PK. Septo-optic dysplasia with unilateral open lip schizencephaly: A case report. Indian J Radiol Imaging 2006;16:321-3. Back to cited text no. 6 Medknow Journal
7. Carman KB, Yarar C, Yakut A, Adapinar B. Septo-optic dysplasia plus: A patient with diabetes insipidus. Pediatr Neurol 2010;43:76-8. Back to cited text no. 7
8. Levine LM, Bhatti MT, Mancuso AA. Septo-optic dysplasia with olfactory tract and bulb hypoplasia. J AAPOS 2001;5:398-9. Back to cited text no. 8
9. Sener RN. Septo-optic dysplasia associated with cerebral cortical dysplasia (cortico-septo-optic dysplasia). J Neuroradiol 1996;23:245-7. Back to cited text no. 9
10. Dobyns WB, Truwit CL. Lissencephaly and other malformations of cortical development: 1995 update. Neuropediatrics 1995;26:132-47. Back to cited text no. 10
Lune AA, Lune SA. Septo-optic dysplasia with pachygyria. Med J DY Patil Univ [serial online] 2014 [cited 2014 Jun 27];7:505-7. Available from: http://www.mjdrdypu.org/text.asp?2014/7/4/505/135288
CASE REPORT
Year : 2014 | Volume : 7 | Issue : 4 | Page : 505-507
Septo-optic dysplasia with pachygyria
Abhay A Lune1, Sonali A Lune2
1 Department of Ophthalmology, Padmashree Dr. D. Y. Patil Medical College, Hospital and Research Centre, Dr. D. Y. Patil Vidyapeeth, Pune, India
2 Department of Ophthalmology, Lune Eye Clinic, Pune, Maharashtra, India
Date of Web Publication 25-Jun-2014
Correspondence Address:
Abhay A Lune
Lune Eye Clinic, 1641, Madhav Heritage, Tilak Road, Pune – 411 030, Maharashtra
India
DOI: 10.4103/0975-2870.135288
