Instituto Valenciano de Microbiología

Masía El Romeral
Ctra. de Bétera a San Antonio Km. 0.3
46117 Bétera (Valencia)
Phone. 96 169 17 02
Fax 96 169 16 37
CIF B-96337217


Anencephaly (Anencephaly) - Gen MTHFR.            

Anencephaly is a disorder that prevents normal development of the brain and skull bones. This alteration occurs when the neural tube does not close during the first week of embryonic development. To not close the neural tube, development of the brain and spinal cord are properly exposed to the amniotic fluid surrounding the fetus in the uterus. This exposure causes the nervous system tissue degenerates. As a result, people with anencephaly are absent certain brain parts and cerebellum. These brain regions are necessary for thought, hearing, vision, emotion and movement coordination. In addition, some skull bones are absent or are incompletely formed. Because of the severity of abnormalities of the nervous system, almost all newborns with anencephaly die before birth or within a few hours or days after birth.

Anencephaly is a complex disorder that is likely due to the interaction of multiple genetic and environmental factors. Some of these factors have been identified, but many remain unknown. Changes in dozens of genes in individuals with anencephaly may influence the risk of developing this type of neural tube defect. The best studied gene is the MTHFR gene, located on the short arm of chromosome 1 (1p36.3). This gene encodes an enzyme called methylenetetrahydrofolate reductase. This enzyme plays a role in processing of amino acids. Methylenetetrahydrofolate reductase is important for a chemical reaction involving forms of folic acid (vitamin B9) vitamin. Specifically, this enzyme converts a molecule called 5,10-methylenetetrahydrofolate to methyltetrahydrofolate molecule 5. This reaction is required for multi - step process that converts the amino acid methionine amino acid homocysteine. The body uses methionine to produce proteins and other important compounds.

Several polymorphisms in the MTHFR gene have been associated with increased risk of neural tube defects. Anencephaly is one of the most common types of NTDs. The best studied polymorphism associated with NTDs change a single nucleotide in MTHFR gene. Specifically, the cytosine nucleotide nucleotide with the thymine is replaced at position 677 (677C> T). People with 677C> T, particularly those with two copies of the genetic variation, have elevated levels of homocysteine in the blood as a result of reduced activity methylenetetrahydrofolate reductase of. Although it is unclear how polymorphisms in the MTHFR gene in individuals with neural tube defects and their mothers, could affect the development of the brain and spinal cord, increased risk of neural tube defects may be related to differences in ability to process folate reductase metilentetrahidrofolato-. A deficiency of this vitamin is a risk factor for neural tube defects.

Most cases of anencephaly are sporadic, meaning that occur in people with no history of disease in your family. Although it has been reported a small percentage of cases in families, it has no clear pattern of inheritance. For parents who have had a child with anencephaly, the risk of having another affected child increases the risk compared to the general population.

Tests in IVAMI: in IVAMI perform detection of mutations associated with anencephaly, by complete PCR amplification of the exons of the MTHFR gene, and subsequent sequencing.

Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).