Title: Septo-Optic Dysplasia Tim Alves
1Septo-Optic DysplasiaTim Alves
2Outline
- Overview
- Etiology
- Epidemiology
- Presentation
- Workup
- Radiologic findings
- Prognosis and Treatment
- Key Points
- References
3Septo-optic dysplasia
- Previously called De Morsier syndrome
- Originally described in 1941 as an absence of the
septum pellucidum with optic nerve abnormalities. - Later updated to include pituitary dysfunction
- There is some controversy regarding diagnostic
criteria, but generally it is a clinical
diagnosis made when at least 2 of 3 classic
criteria are met - Optic nerve hypoplasia
- Pituitary hormone abnormalities
- Midline brain defects, including agenesis of the
septum pellucidum and/or corpus callosum
4Etiology
- Early forebrain developmental abnormality
- Disorder of midline ventral prosencephalic
development (4th to 6th week of gestation)
including optic nerves, forebrain, olfactory
bulbs, septum pellucidum, corpus callosum, and
pituitary gland - Most cases sporadic/idiopathic
5Etiology, cont.
- Genetic basis?
- AD and AR patterns have been described, two genes
identified HESX1 and SOX2 - Genetic diagnosis made in lt1 of cases
- Environmental?
- Associated with maternal diabetes, quinidine
ingestion, antiseizure medications, drug abuse,
CMV infection, and congenital brain malformations - Multifactorial
6Epidemiology
- 1 in 10,000 to 1 in 50,000
- More common in children born to younger mothers
and first-borns - MF, no ethnic predilection
7Uncertain classification
- Heterogeneous, variable features and severity
- Syndrome vs. complex
- Continuum
- Milder form of lobar holoprosencephaly?
- Milder forms of SOD?
8Presentation
- Generally two presentations
- At birth, in association with multiple congenital
anomalies seizures, apnea, cyanosis, hypotonia,
jaundice, microphallus - Later on in childhood, with growth failure and/or
visual abnormalities - Approx. 50 do not have a schizencephaly this
group tends to present with endocrine dysfunction - Approx. 50 of patients with SOD have a
schizencephaly and present with seizures, almost
normal visual apparatus, generally normal
endocrine function SOD plus
9Associated Clinical Findings
- Developmental delay
- Seizures
- Visual impairment
- Sleep disturbances
- Precocious puberty
- Obesity
- Anosmia
- SNHL
- Cardiac anomalies
10Diagnostic Workup
- History visual problems, symptoms of hormonal
deficiencies, other congenital and developmental
abnormalities - Opthalmologic exam optic nerve hypoplasia
- Tests of pituitary function
- MR is the best imaging modality
11MRI Findings in SOD
- Optic nerve hypoplasia/dysplasia, unilateral or
bilateral - Agenesis of the septum pellucidum
- Abnormalities of the corpus callosum and
hypothalamo-pituitary axis - Thin pituitary stalk, small anterior pituitary,
posterior pituitary ectopia - Findings are variable, and also include
- Olfactory nerve hypoplasia, schizencephaly,
cortical dysplasias and heterotopia.
12MR shows absent septum pellucidum, typical flat
ventricular roof, pointy frontal horns, absent
pituitary stalk and ectopic posterior lobe.
13Images show absent septum pellucidum, hypoplastic
pituitary stalk and calloso-forniceal
continuation.
14Significantly hypoplastic right optic nerve,
ipsilateral to close lip schizencephaly is
probably not SOD.
15The optic nerves are very small as is the optic
chiasm and pituitary stalk, the septum pellucidum
is absent.
16Imaging Differential Diagnosis
- Lobar holoprosencephaly similar to SOD but has
lack of separation (fusion) of cerebral
hemispheres, SOD is considered by some to be a
milder form of this disorder - Overlap syndromes Optic-infundibular dysplasia
(OID) - normal septum Schizencephaly - Isolated ectopic posterior pituitary lobe normal
optic chiasm/nerves, normal septum - Kallmann Syndrome- absent or dysplastic olfactory
nerves/ olfactory sulci, hypogonadotropic
hypogonadism, occasionally associated with
visual, septal, or pituitary abnormalities
17Prognosis and Treatment
- Variable morbidity and prognosis - depends on
associated brain and pituitary malformations - Possible hypothalamic and pituitary crises
sudden death from hypocortisolism - Treatment Hormone replacement therapy
18Key points
- Classically optic nerve hypoplasia, pituitary
hormone abnormalities, and absent septum
pellucidum - Disorder of early prosencephalic development with
varying presentations and degrees of severity - Mainly a clinical diagnosis
- Exact criteria and classification is debatable
- Continuum?
- Majority of cases are idiopathic/sporadic, but
genetic and environmental causes have been
identified - MRI of the brain plays a key role in diagnosis
- Key findings
- Quickly narrows down a broad clinical
differential diagnosis
19References
- Adam, A. Grainger Allisons Diagnostic
Radiology, 5th ed. 2008. Ch 70, Malformations of
commissural and related structures Figure 70.11 - Barkovich AJ. Diagnostic Imaging Pediatric
Neuroradiology, 1st edition, 2007. Amirsys. I5
10-13. - Castillo M. Neuroradiology Companion Methods,
Guidelines, and Imaging Fundamentals, 3rd ed.
2006. p212-213. - Hahn JS and Barnes PD. Neuroimaging advances in
holoprosencephaly Refining the spectrum of the
midline malformation. Am J Med Genet C Semin Med
Genet. 2010 Feb 15154C(1)120-32. - Webb EA, Dattani MT. Septo-optic dysplasia.
European Journal of Human Genetics. 2010
18393-397.