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

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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