Deficit di MTHFR per i pazienti
Test Genetici

Author: Gianpiero Pescarmona
Date: 23/07/2023

Description

L'MTHFR (metilen-tetraidrofolato-riduttasi) è un enzima che catalizza la reazione

5,10-metilene-TH4F --> 5-metil-TH4F

Il 5-metil-TH4F è indispensabile per la sintesi della metionina.

La disponibilità di metionina nell'organismo dipende quindi:

  • dall'introduzione di proteine ricche di metionina
  • dal'acido folico
  • dalla vitamina B12
  • dall'attività della MTHFR (di cui esistono due varianti C677T e A1298C, con attività ridotta)

Nei soggetti portatori in forma omozigote o con doppia eterozigosi (il 10% della popolazione italiana) ci si possono attendere bassi livelli di metionina.

I sintomi che possono derivare da questa situazione metabolica sono praticamente infiniti, visto le reazioni che richiedono la metionina.

Reazioni di metilazione, attraverso la donazione di un metile da parte della S-adenosil-Metionina (SAME) a substrati diversi:

  • DNA (DNA ipometilato si associa a maggior frequenza di tumori)
  • RNA
  • Proteine (la metilazione protegge da autoanticorpi: sclerosi multipla, Tiroiditi auto immuni )
    • Arginine
    • Lysine
  • Lipidi (trombosi da IgG anti fosfolipidi)
  • Ormoni e neurotransmettitori (istamina, Serotonina, Dopamina, vengono inattivati)
  • Telomero (la metilazione protegge il telomero dall'accorciamento, permettendo una vita più lunga grazie ad una conservata sintesi proteica anche nell'anziano)

Inoltre, in carenza di metionina,

  • aumentano le proteine povere di metionina, come il TNF alpha (aumento della risposta infiammatoria, più PCR, più fibrinogeno, più trombosi e crescita rapida tumori.
  • diminuiscono le molecole ricche di metili: colina e carnitina
    • colina precursore di ceramide e acetilcolina
    • carnitina necessaria per il catabolismo degli acidi grassi, fonte principale di energia per le cellule muscolari e endoteliali (fragilità capillare e placche aterosclerotiche)

Per avere una idea intuitiva di cosa può significare avere la metionina bassa, basta pensare che i portatori di sindrome di Down hanno la metionina bassa per motivi genetici (bassa omocisteina)

La somministrazione di

Colina
Carnitina
Metionina

Può permettere di annullare i fattori di rischio derivanti dal difetto genetico

Comments
2023-07-23T15:02:01 - Gianpiero Pescarmona
2023-07-23T14:49:21 - Gianpiero Pescarmona

mthfr+induction+promoter

Increased MTHFR promoter methylation in mothers of Down syndrome individuals, 2016

Abstract
Despite that advanced maternal age at conception represents the major risk factor for the birth of a child with Down syndrome (DS), most of DS babies are born from women aging less than 35 years. Studies performed in peripheral lymphocytes of those women revealed several markers of global genome instability, including an increased frequency of micronuclei, shorter telomeres and impaired global DNA methylation. Furthermore, young mothers of DS individuals (MDS) are at increased risk to develop dementia later in life, suggesting that they might be “biologically older” than mothers of euploid babies of similar age.

Mutations in folate pathway genes, and particularly in the methylenetetrahydrofolate reductase (MTHFR) one, have been often associated with maternal risk for a DS birth as well as with risk of dementia in the elderly. Recent studies pointed out that also changes in MTHFR methylation levels can contribute to human disease, but nothing is known about MTHFR methylation in MDS tissues.

We investigated MTHFR promoter methylation in DNA extracted from perypheral lymphocytes of 40 MDS and 44 matched control women that coinceived their children before 35 years of age, observing a significantly increased MTHFR promoter methylation in the first group (33.3 ± 8.1% vs. 28.3 ± 5.8%; p = 0.001). In addition, the frequency of micronucleated lymphocytes was available from the women included in the study, was higher in MDS than control mothers (16.1 ± 8.6‰ vs. 10.5 ± 4.3‰; p = 0.0004), and correlated with MTHFR promoter methylation levels (r = 0.33; p = 0.006).

Present data suggest that MTHFR epimutations are likely to contribute to the increased genomic instability observed in cells from MDS, and could play a role in the risk of birth of a child with DS as well as in the onset of age related diseases in those women.

Valproic acid increases expression of methylenetetrahydrofolate reductase (MTHFR) and induces lower teratogenicity in MTHFR deficiency, 2008

Abstract
Valproate (VPA) treatment in pregnancy leads to congenital anomalies, possibly by disrupting folate or homocysteine metabolism. Since methylenetetrahydrofolate reductase (MTHFR) is a key enzyme of folate interconversion and homocysteine metabolism, we addressed the possibility that VPA might have different teratogenicity in Mthfr+/+ and Mthfr+/− mice and that VPA might interfere with folate metabolism through MTHFR modulation. Mthfr+/+ and Mthfr+/− pregnant mice were injected with VPA on gestational day 8.5; resorption rates and occurrence of neural tube defects (NTDs) were examined on gestational day 14.5. We also examined the effects of VPA on MTHFR expression in HepG2 cells and on MTHFR activity and homocysteine levels in mice. Mthfr+/+ mice had increased resorption rates (36%) after VPA treatment, compared to saline treatment (10%), whereas resorption rates were similar in Mthfr+/− mice with the two treatments (25–27%). NTDs were only observed in one group (VPA-treated Mthfr+/+). In HepG2 cells, VPA increased MTHFR promoter activity and MTHFR mRNA and protein (2.5- and 3.7-fold, respectively). Consistent with cellular MTHFR upregulation by VPA, brain MTHFR enzyme activity was increased and plasma homocysteine was decreased in VPA-treated pregnant mice compared to saline-treated animals. These results underscore the importance of folate interconversion in VPA-induced teratogenicity, since VPA increases MTHFR expression and has lower teratogenic potential in MTHFR deficiency. J. Cell. Biochem. 105: 467–476, 2008. © 2008 Wiley-Liss, Inc.

Correlation of methylation status in MTHFR promoter region with recurrent pregnancy loss, 2021

Background
DNA methylation is an epigenetic process for modifying transcription factors in various genes. Methylenetetrahydrofolate reductase (MTHFR) stimulates synthesis of methyl radical in the homocysteine cycle and delivers methyl groups needed in DNA methylation. Furthermore, numerous studies have linked gene polymorphisms of this enzyme with a larger risk of recurrent pregnancy loss (RPL), yet scarce information is available concerning the association between epigenetic deviations in this gene and RPL. Hypermethylation at precise DNA sequences can function as biomarkers for a diversity of diseases. We aimed by this study to evaluate the methylation status of the promoter region of MTHFR gene in women with RPL compared to healthy fertile women. It is a case–control study. Hundred RPL patients and hundred healthy fertile women with no history of RPL as controls were recruited. MTHFR C677T was assessed by polymerase chain reaction-restriction fragment length polymorphism (RFLP). Quantitative evaluation of DNA methylation was performed by high-resolution melt analysis by real-time PCR.

Results
The median of percentage of MTHFR promoter methylation in RPL cases was 6.45 [0.74–100] vs. controls was 4.50 [0.60–91.7], P value < 0.001. In the case group, 57 hypermethylated and 43 normo-methylated among RPL patients vs. 40 hypermethylated and 60 normo-methylated among controls, P< 0.005. Frequency of T allele in C677T MTHFR gene among RPL patients was 29% vs. 23% among the control group; C allele vs. T allele: odds ratio (OR) = 1.367 (95% confidence interval (CI) 0.725–2.581).

Conclusion
Findings suggested a significant association between hypermethylation of the MTHFR promoter region in RPL patients compared to healthy fertile women.

Ipermetilazione blocca espressione MTHFR e le donne abortiscono

estrogens+and+DNA+hypermethylation

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