Septo-optic dysplasia
Encyclopedia
Septo-optic dysplasia also known as de Morsier syndrome is a congenital
malformation syndrome
made manifest by hypoplasia (underdevelopment) of the optic nerve
and absence of the septum pellucidum
(a midline part of the brain
). Vision in each eye can be unaffected, partially lost, or in some patients, completely absent.
Although not included in the name, hypopituitarism
is sometimes included in the definition.
Neuroradiologically, intracranial malformations associated with septo-optic dysplasia include agenesis
of the septum pellucidum
, schizencephaly
, and lobar holoprosencephaly
.
. If severe, it can lead to diagnosis in the first days of life by causing hypoglycemia
, jaundice
, and micropenis
(if a boy). The cause of the jaundice is unknown, and an unusual aspect of it (compared to most neonatal jaundice
) is that it can be largely a conjugated (direct) hyperbilirubinemia suggestive of obstructive liver
disease. It typically resolves over several weeks once hormone replacement is begun. All of the pituitary hormones can be replaced, and this is the treatment for deficiencies. Septo-optic dysplasia is one of the most common forms of congenital growth hormone deficiency.
s sometimes occur. Prediction of intellectual outcome in infancy is difficult. Various types of early intervention or equivalent programs can help a child reach full developmental potential.
). In addition, mutations of the neuronal guidance cue netrin and of its receptor DCC have been implicated in De Morsier's syndrome (Serafini et al. 1996, Fazeli et al. 1997, Deiner et al. 1997) but in most cases SOD is a sporadic birth defect of unknown cause and does not recur again with subsequent pregnancies.
brain development of a fetus. Specifically, in utero cocaine
exposure has been linked to the development of septo-optic dysplasia.
has been implicated as a possible etiology of septo-optic dysplasia.
Congenital disorder
A congenital disorder, or congenital disease, is a condition existing at birth and often before birth, or that develops during the first month of life , regardless of causation...
malformation syndrome
Syndrome
In medicine and psychology, a syndrome is the association of several clinically recognizable features, signs , symptoms , phenomena or characteristics that often occur together, so that the presence of one or more features alerts the physician to the possible presence of the others...
made manifest by hypoplasia (underdevelopment) of the optic nerve
Optic nerve
The optic nerve, also called cranial nerve 2, transmits visual information from the retina to the brain. Derived from the embryonic retinal ganglion cell, a diverticulum located in the diencephalon, the optic nerve doesn't regenerate after transection.-Anatomy:The optic nerve is the second of...
and absence of the septum pellucidum
Septum pellucidum
The septum pellucidum , and not to be confused with the medial septum, is a thin, triangular, vertical membrane separating the anterior horns of the left and right lateral ventricles of the brain...
(a midline part of the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
). Vision in each eye can be unaffected, partially lost, or in some patients, completely absent.
Although not included in the name, hypopituitarism
Hypopituitarism
Hypopituitarism is the decreased secretion of one or more of the eight hormones normally produced by the pituitary gland at the base of the brain...
is sometimes included in the definition.
Neuroradiologically, intracranial malformations associated with septo-optic dysplasia include agenesis
Agenesis
In medicine, agenesis refers to the failure of an organ to develop during embryonic growth and development due to the absence of primordial tissue...
of the septum pellucidum
Septum pellucidum
The septum pellucidum , and not to be confused with the medial septum, is a thin, triangular, vertical membrane separating the anterior horns of the left and right lateral ventricles of the brain...
, schizencephaly
Schizencephaly
Schizencephaly is a rare grey matter malformation of the brain. It belongs to the group of malformations of the central nervous system.-Presentation:...
, and lobar holoprosencephaly
Holoprosencephaly
Holoprosencephaly is a cephalic disorder in which the prosencephalon fails to develop into two hemispheres. Normally, the forebrain is formed and the face begins to develop in the fifth and sixth weeks of human pregnancy...
.
Optic nerve
The optic nerve hypoplasia is generally manifested by nystagmus (involuntary eye movements, often side-to-side) and a smaller-than-usual optic disc. The degree of visual impairment is variable, and ranges from normal vision to complete blindness. When nystagmus develops, it typically appears by 1–8 months of age, and usually indicates that there will be a significant degree of visual impairment, but the severity is difficult to predict in infancy. Although there are many measures to compensate for visual impairment, there are few treatments available to induce normal optic nerve function.Pituitary
The degree of pituitary deficiency is also variable, and ranges from normal function, to deficiency of a, to deficiency of both anterior and posterior hormones. It is often unclear if the hypopituitarism is due to a primary pituitary dysfunction or is secondary to a hypothalmic dysfunction. Hypopituitarism in this syndrome is most often manifested by growth hormone deficiencyGrowth hormone deficiency
Growth hormone deficiency is a medical condition in which the body does not produce enough growth hormone . Growth hormone, also called somatotropin, is a polypeptide hormone which stimulates growth and cell reproduction...
. If severe, it can lead to diagnosis in the first days of life by causing hypoglycemia
Hypoglycemia
Hypoglycemia or hypoglycæmia is the medical term for a state produced by a lower than normal level of blood glucose. The term literally means "under-sweet blood"...
, jaundice
Jaundice
Jaundice is a yellowish pigmentation of the skin, the conjunctival membranes over the sclerae , and other mucous membranes caused by hyperbilirubinemia . This hyperbilirubinemia subsequently causes increased levels of bilirubin in the extracellular fluid...
, and micropenis
Micropenis
Micropenis is an unusually small penis. A common criterion is a dorsal erect penile length of at least 2.5 standard deviations smaller than the mean human penis size. The condition is usually recognized shortly after birth...
(if a boy). The cause of the jaundice is unknown, and an unusual aspect of it (compared to most neonatal jaundice
Neonatal jaundice
Neonatal jaundice or Neonatal hyperbilirubinemia is a yellowing of the skin and other tissues of a newborn infant. A bilirubin level of more than 85 umol/l manifests clinical jaundice in neonates whereas in adults a level of 34 umol/l would look icteric...
) is that it can be largely a conjugated (direct) hyperbilirubinemia suggestive of obstructive liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
disease. It typically resolves over several weeks once hormone replacement is begun. All of the pituitary hormones can be replaced, and this is the treatment for deficiencies. Septo-optic dysplasia is one of the most common forms of congenital growth hormone deficiency.
Septum pellucidum
The brain effects are also variable. SeizureSeizure
An epileptic seizure, occasionally referred to as a fit, is defined as a transient symptom of "abnormal excessive or synchronous neuronal activity in the brain". The outward effect can be as dramatic as a wild thrashing movement or as mild as a brief loss of awareness...
s sometimes occur. Prediction of intellectual outcome in infancy is difficult. Various types of early intervention or equivalent programs can help a child reach full developmental potential.
Variability
Septo-optic dysplasia is a highly variable disorder. It is rare for siblings to present with identical features of the Septo-optic dysplasia spectrum. Many patients present with additional developmental defects outside the Septo-optic dysplasia triad. In particular digital defects are common.Causes
Septo-optic dysplasia is a developmental disorder resulting from a defect of normal embryological development. There is no single cause of septo-optic dysplasia. Septo-optic dysplasia has been linked to young maternal age.Genetic
Rare familial recurrence has been reported, suggesting at least one genetic form (HESX1HESX1
Homeobox expressed in ES cells 1, also known as homeobox protein ANF, is a homeobox protein that in humans is encoded by the HESX1 gene.Expression of HEX1 and HESX1 marks the anterior visceral endoderm of the embryo...
). In addition, mutations of the neuronal guidance cue netrin and of its receptor DCC have been implicated in De Morsier's syndrome (Serafini et al. 1996, Fazeli et al. 1997, Deiner et al. 1997) but in most cases SOD is a sporadic birth defect of unknown cause and does not recur again with subsequent pregnancies.
In utero cocaine exposure
Environmental factors including exposure to recreational drugs can potentially interfere with the in uteroIn utero
In utero is a Latin term literally meaning "in the womb". In biology, the phrase describes the state of an embryo or fetus. In legal contexts, the phrase is used to refer to unborn children. Under common law, unborn children are still considered to exist for property transfer purposes.-See also:*...
brain development of a fetus. Specifically, in utero cocaine
Cocaine
Cocaine is a crystalline tropane alkaloid that is obtained from the leaves of the coca plant. The name comes from "coca" in addition to the alkaloid suffix -ine, forming cocaine. It is a stimulant of the central nervous system, an appetite suppressant, and a topical anesthetic...
exposure has been linked to the development of septo-optic dysplasia.
Valproate toxicity
Valproate toxicity in uteroIn utero
In utero is a Latin term literally meaning "in the womb". In biology, the phrase describes the state of an embryo or fetus. In legal contexts, the phrase is used to refer to unborn children. Under common law, unborn children are still considered to exist for property transfer purposes.-See also:*...
has been implicated as a possible etiology of septo-optic dysplasia.