Association of CYP2D6 100 C > T and 2850 C > T polymorphisms with generalized tonic clonic seizures among Indians

The potential impact of CYP2D6 (*2/*4/*10) gene variants among Egyptian epileptic children: A preliminary study

BACKGROUND

The cytochrome P450 (CYP) isoenzymes have an indispensable role in the metabolic phase of different medications during the treatment of multiple neuropsychiatric disorders. The foremost goal of this study is to evaluate the correlation of the allelic variants within CYP2D6 (*2/*4/*10) gene with the susceptibility for epileptic syndrome as well as the assessment the degree of resistance towards antiepileptic drugs (AEDs).

METHODS

This work was designed based on the involvement of 200 participants [100 unrelated healthy controls, 50 AEDs responsive, and 50 AEDs resistant]. Genomic DNA for the CYP2D6 variants was genotyped utilizing the T-ARMS-PCR technique.

RESULTS

The distributions of the CYP2D6*2 (rs16947; c.886C > T) and CYP2D6*4 (rs3892097; c.506-1G > A) variants were significantly correlated with elevated risk among epileptic patients compared to healthy controls (P-value < 0.05). Furthermore, the CYP2D6*2 variant was statistically associated with disease risk among AEDs responsive patients, while the CYP2D6*4 variant was statistically correlated with disease risk among AEDs resistant patients (P-value < 0.05). Interestingly, the allelic variants of the CYP2D6*4 (A allele) and CYP2D6*10 (T allele) were associated with elevated risk among AEDs resistant compared to AEDs responsive patients (P-value = 0.008 and 0.040, respectively).

CONCLUSIONS

The CYP2D6*2 and CYP2D6*4 variants were recognized as independent risk factors among epileptic patients, but not the CYP2D6*10 variant.

Distribution of CYP2D6 genotypes in the Indian population - preliminary report

Background

Cytochrome P450 2D6 (CYP2D6) allelic distribution exhibits differences amongst worldwide populations. There is lack of data from Mumbai, Western India, on the major CYP2D6 alleles *2, *3, *4, *5, *10 and *41, and gene multiplication alleles. Hence, the present study was undertaken to determine the distribution of these clinically relevant CYP2D6 alleles.

Methods

Fifty-two healthy individuals were screened using TaqMan SNP genotyping and copy number variation (CNV) assays by real-time polymerase chain reaction.

Results

The allele frequencies of CYP2D6*2, *3, *4, *5, *10 and *41 alleles were observed to be 30.8%, 0%, 11.5%, 3.9%, 19.2% and 17.3%, respectively. The frequency of CYP2D6 gene one copy, two copies, three copies and four copies were observed to be 7.7%, 76.9%, 13.5% and 1.9%, respectively. The predicted phenotype frequency was observed to be 78.9%, 3.9% and 9.6% for extensive, intermediate, and ultrarapid metabolizers, respectively, whereas poor metabolizers were not detected.

Conclusions

CYP2D6 allele frequencies showed heterogeneous distribution in the present study as compared to worldwide populations. High frequency of CYP2D6*41 allele, gene duplication alleles and UMs was observed. The scarcity and/or lack of data from the Indian population on these alleles further substantiates the need for screening of CYP2D6 genotyping.

Pharmacogenetics and gender association with psychotic episodes on nortriptyline lower doses: patient cases

The variation in individual responses to psychotropic drug treatment remains a critical problem in the management of psychotic disorders. Although most patients will experience remission, some patients may develop drug-induced adverse effects that may range from troublesome to life threatening. Antidepressants are freely prescribed by general practitioners, and there should be constant awareness in the medical community about possible serious side effects. We describe two cases of adverse drug reactions on low dosage treatment that led to extreme psychotic episodes as examples of the potential for dangerous side effects. The patients developed adverse reactions on the normal recommended dosage of nortriptyline, a tricyclics antidepressant (TCA). Both were females, with no history of antidepressant treatment, unsocial behaviour, nor any family history of psychosis, but both experienced severe psychiatric symptoms. Pharmacogenetic tests can easily be performed and interpreted according to the likelihood of adverse reactions and should be included in toxicity interpretation.