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Neural Tube

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Neutral tube defects are congenital abnormalities of CNs that develop because of mal
exact data is available but in Pakistan it has a prevalence rate of 4.5/1000 total births.
There are 2 types of defects.
union of neural folds completely. It has an incidence of 300000/yr over worldwide. No
Open
Closed
Open neural tube defects are most common. Open NTD occur when brain or spinal
cord are exposed at birth through a hole in the skull or vertebrae.
In open category included are anencephaly, encephalocele, hydrocephaly,
schizocephaly, spina bifida rare varieties are closed defects which occur when spinal
defect is covered by skin. These include,meningocele, myeilomeningocle and tethered
cord.
There are multiple causative agents of these defects. There are genetics reasons plus
environmental. There are deficient studies on genetics but multiple nutritional factors
cameout on front lines at their supply to pregnant ladies prevented the defects.
Numerous Genetic functioning abnormality, regularity of membrane morphology is
essential for normal closing.
Multifactorial Threshold Model is applied in development of NTD since single genetic
aberration is insufficient to cause defect. There is interaction of genes to genes and
genes to environment to cause the defect.
EMBRYOLOGY
Formation of Neutral tubes involves the bending of neuroepithelium at midline to
generate neural folds. These neural folds elevate and fuse in the midline in a process

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called (Primary Neurulation). If incomplete closure neural tube is exposed to
environment and undergoes degeneration so that neuronal deficit develops. The
severity of defeats depends on which axis is deficient. If fusion of brain affected, then
defeat like anencepaly develops and if spinal cord affected then spinal bifida like
abnormalities come out. NTD can be due to either failure of initiatin events or
disturbance of closing events at these sites. this process of primary Neuralation take
place at 18 days after fertilization when mostly women do not know that they are
pregnant + process complete till 28 days after fertilization.
Secondary Neurulation This is the process by which neural tube below to the mid
sacral region is continue with the lower end primary neural tube forms. There is a
population of tail bud cells that condense here to form an epithelial rod which canalizes
to form tube lumen in lower sacral and coccygeal region. There is skin covered
malformation which makes ectopic lipomaous materials by spinal cord tethering.
Genetics
There are certain transcriptional regulators and proteins which affect structure of
chromatin which are mandatory for natural tube closure. Sonic heg hog signals ate over
active for there is erroneous functions of planner cell pathway which are main causes of
NTD. Genetics variations in folate metabolism due to single nucleotide polymorphism at
methylene tetrahydrofolate reductase.
Prevalence
Polymorphism at methylene tetra hydro folate reductase community based
observational studies 8 how 3.2 million children are affected with defeat every year.

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Neutral tube defects are congenital abnormalities of CNs that develop because of mal exact data is available but in Pakistan it has a prevalence rate of 4.5/1000 total births. There are 2 types of defects. union of neural folds completely. It has an incidence of 300000/yr over worldwide. No Open Closed Open neural tube defects are most common. Open NTD occur when brain or spinal cord are exposed at birth through a hole in the skull or vertebrae. In open category included are anencephaly, encephalocele, hydrocephaly, schizocephaly, spina bifida rare varieties are closed defects which occur when spinal defect is covered by skin. These include,meningocele, myeilomeningocle and tethered cord. There are multiple causative agents of these defects. There are genetics reasons plus environmental. There are deficient studies on genetics but multiple nutritional factors cameout on front lines at their supply to pregnant ladies prevented the defects. Numerous Genetic functioning abnormality, regularity of membrane morphology is essential for normal closing. Multifactorial Threshold Model is applied in development of NTD since single genetic aberration is insufficient to cause defect. There is interaction of genes to genes and genes to environment to cause the defect. EMBRYOLOGY Formation of Neutral tubes involves the bending of neuroepithelium at midline to generate neural folds. These neural folds elevate and fuse in the midline in a process called (Primary Neurulation). If incom ...
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