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  1. 1. SEPTO-OPTIC DYSPLASIA
  2. 2. SOD: Definition <ul><li>Variable combination of midline forebrain abnormalities, eye abnormalities and pituitary abnormalities </li></ul><ul><li>Rare: reported incidence 1/50000; probably commoner </li></ul><ul><li>2/3 features to make the diagnosis </li></ul><ul><li>Commoner in younger mothers </li></ul>
  3. 3. Forebrain abnormalities <ul><li>In 75-80% of patients </li></ul><ul><li>Absence of septum pellucidum </li></ul><ul><li>Absence of corpus callosum </li></ul><ul><li>Cerebellar hypoplasia </li></ul><ul><li>Schizencephaly </li></ul>
  4. 4. Consequences of forebrain anomalies <ul><li>Fits </li></ul><ul><li>Behavioural difficulties </li></ul><ul><li>Learning difficulties </li></ul><ul><li>Developmental delay </li></ul><ul><li>Hemiplegia </li></ul>
  5. 5. Optic nerve hypoplasia <ul><li>Unilateral/bilateral </li></ul><ul><li>Bilateral commoner </li></ul><ul><li>Associated with anopthalmia/micropthalmia </li></ul><ul><li>Visual impairment variable - complete to compensated </li></ul>
  6. 6. Pituitary gland <ul><li>Develops from the oral cavity in the embryo and the brain (hypothalamus) </li></ul><ul><li>5 different cell types in anterior pituitary producing 6 different hormones </li></ul><ul><li>Secretion of hormones regulated by hypothalamus </li></ul>
  7. 7. Anterior pituitary gland <ul><li>Growth hormone: growth and helps maintain normal blood sugar levels in children; increases bone strength, muscle mass and decreases fat mass and heart disease in adults </li></ul><ul><li>ACTH: regulates production of cortisol and androgens from adrenal glands; cortisol essential for normal well-being and to fight stress and infection </li></ul>
  8. 8. Anterior pituitary gland <ul><li>Prolactin: important for lactation, ?immune system </li></ul><ul><li>FSH, LH: important for puberty and fertility; LH important for normal development of males and for descent of testes into scrotum </li></ul><ul><li>TSH: important for regulation of thyroid gland and thyroxine production </li></ul>
  9. 9. Posterior pituitary gland <ul><li>Vasopressin: important for normal fluid balance - retains water by controlling reabsorption of water in kidney tubules </li></ul><ul><li>Oxytocin: important for parturition (birth) and ejection of milk </li></ul>
  10. 10. Pituitary Hormone Deficiency <ul><li>GH: poor growth with eventual short stature, possibly increased incidence of myocardial infarction </li></ul><ul><li>Prolactin: no lactation </li></ul><ul><li>ACTH: low cortisol leading to low blood sugar, lethargy, inability to fight stress and infection, low blood pressure, low sodium level in blood, collapse </li></ul>
  11. 11. Pituitary Hormone Deficiency <ul><li>FSH, LH: inadequate sexual development in males, lack of puberty, lack of fertility </li></ul><ul><li>TSH: lack of thyroxine with slowness, cold intolerance, constipation, growth failure, mental retardation if not picked up early </li></ul><ul><li>Vasopressin: diabetes insipidus with excessive urinary output </li></ul>
  12. 12. Complexity of hypothalamo-pituitary development <ul><li>Early puberty: can be explained on basis of hypothalamic involvement </li></ul><ul><li>Occasionally mixed involvement of hypothalamus and pituitary </li></ul>
  13. 13. Clinical features of SOD <ul><li>Conjugated jaundice </li></ul><ul><li>Neurological features </li></ul><ul><li>Variable visual loss </li></ul><ul><li>Impaired sense of smell </li></ul><ul><li>Endocrine features </li></ul><ul><li>Behavioural disturbances eg. autism </li></ul><ul><li>Sleep disturbance </li></ul>
  14. 14. MRI SCANS OF SOD PATIENTS CONTROL SIBLING 2 SIBLING 1
  15. 15. Management of SOD <ul><li>Support from Neurologists and Opthalmologists: treatment of convulsions </li></ul><ul><li>Mainstay of treatment: endocrine </li></ul>
  16. 16. Endocrine replacement <ul><li>Growth hormone: daily subcutaneous injections </li></ul><ul><li>Hydrocortisone: X3 doses daily; adjustment with illness/stress </li></ul><ul><li>DDAVP: nasal/oral </li></ul><ul><li>Thyroxine </li></ul><ul><li>Ethinyloestradiol/testosterone </li></ul>
  17. 17. Investigations <ul><li>MRI scan of brain </li></ul><ul><li>Visual evoked responses/electroretinogram </li></ul><ul><li>Routine electrolyte measurement </li></ul><ul><li>Thyroid function tests </li></ul><ul><li>Pituitary function tests: glucagon/insulin/LHRH/TRH - in tertiary centres ideally </li></ul><ul><li>Fluid balance </li></ul>
  18. 18. Monitoring <ul><li>Evolving - new endocrine features may develop </li></ul><ul><li>Monitoring of growth rate at regular intervals </li></ul><ul><li>Monitoring through puberty </li></ul><ul><li>Regular checks of thyroid function, watch fluid balance </li></ul>
  19. 19. Long-term outlook <ul><li>Short stature </li></ul><ul><li>Developmental/intellectual impairment </li></ul><ul><li>Fits, hemiparesis etc </li></ul><ul><li>Impaired fertility </li></ul><ul><li>Visual impairment </li></ul><ul><li>Sleep/behavioural difficulties </li></ul><ul><li>Obesity </li></ul>
  20. 20. Why do you get SOD? <ul><li>Development of pituitary gland, forebrain, olfactory bulbs and eyes all from the same part of the early embryo. Problems occur at 3-6 weeks of gestation </li></ul><ul><li>Environment and teratogens </li></ul><ul><li>Familial cases: dominant or recessive </li></ul>
  21. 21. Genetics of SOD <ul><li>Mutations in HESX1 : Dominant or recessive </li></ul><ul><li>Occasionally, one abnormal copy of gene carried with no phenotype in parent but child affected </li></ul><ul><li>Number of other developmental genes may also be involved: all extrapolated from animal studies </li></ul>
  22. 22. Research <ul><li>New genes involved in SOD: what is their function </li></ul><ul><li>Why the variability in severity </li></ul><ul><li>Sleep/wake cycles in children with SOD and hypothalamic involvement and the use of mel a tonin (10-18 year olds) </li></ul>

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