Expanded carrier screening in gamete donors of Venezuela

Urbina, María Teresa; Benjamin, Isaac; Medina, Rubén Danilo Méndez; Jiménez, José Manuel Seguí; Trías, Laura; Lerner, Jorge

doi:10.5935/1518-0557.20170062

Cited by 3 publications

(4 citation statements)

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“…Genetic counseling in the gamete donation process includes the process of explaining genetic inheritance and the contribution of genetic factors to disease and exploring indicators of a high penetrance genetic disorder in a donor´s personal or familial history ( Castilla et al ., 2020 ). The health professional responsible for this counseling varies in different countries, with physicians, nurses, or genetic counselors delivering this information, with or without specific training in this field ( Dondorp et al ., 2014 ; Urbina et al ., 2017 ). Under the Portuguese Law 12/2005 ( Assembleia da República, 2005 ; Ministério da Saúde, 2014 ), genetic counseling and carrier screening are activities only performed by a physician with training in Medical Genetics.…”

Section: Discussionmentioning

confidence: 99%

“…Nevertheless, the access to genetic counseling by trained professionals is a challenge worldwide, with many countries not recognizing the genetic counselor profession. In the coming years, the health care professionals involved in the gamete donation process should reflect about the competence level that should be required to the professionals performing the genetic counseling and carrier screening in the gamete donation candidates ( Urbina et al ., 2017 ), with the active participation of donors and recipients ( Amor et al ., 2018 ).…”

Section: Discussionmentioning

confidence: 99%

“…As more authors are discussing the inclusion of a long list of genes for carrier screening, as an expanded carrier screening (ECS), it is expected that the proportion of candidates with findings would increase, with studies describing carrier rates of 24%-41%, listing different screened genes ( Lazarin et al ., 2013 ; Mertes et al ., 2018 ; Payne et al ., 2021 ; Urbina et al ., 2017 ). A donor-recipient genetic matching system, to decrease the probability of combining two affected alleles in autosomal recessive disorders, has been proposed, and it is recommended in some countries, such as in Spain ( Castilla et al ., 2020 ).…”

Section: Discussionmentioning

confidence: 99%

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Genetic counseling and carrier screening in candidates for gamete donation at a Portuguese center

Soares¹,

Tkachenko²,

Fernandes³

et al. 2022

JBRA

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Objective: Genetic counseling and carrier screening are part of the gamete donation process by healthy individuals. We aim to review the findings of genetic counseling and carrier screening of a cohort of candidates at our public gametes bank.Methods: Thirty-four male and 64 female candidates had genetic counseling with a medical geneticist before donation. Of these, one female candidate voluntarily dropped-out. Thirty-four males and 63 females performed karyotype and screening for the more common pathogenic variants for CFTR-related cystic fibrosis and spinal muscular atrophy (SMN1) in the Portuguese population. In addition, all females also performed Fragile X expansion screening (FMR1). Thirty candidates with known or assumed African ancestry performed hemoglobinopathies screening.Results: Six candidates were definitely or temporarily withheld from the donation process given their family or personal history that required further investigation. Of 97 candidates tested, 16.5% presented anomalous laboratory results (16/97): ten candidates were carriers for an autosomal recessive disorder -cystic fibrosis (5/97), sickle cell anemia (3/30), and spinal muscular atrophy (2/97). One female was an FMR1 pre-mutation carrier (1/63). One female candidate presented with triple X mosaicism: 47,XXX[2]/46,XX [50]. Two candidates presented with chromosomal instability of unknown origin. In one candidate, a mosaic for the Philadelphia chromosome was detected, revealing the diagnosis of chronic myeloid leukemia.Conclusions: From a cohort of 97 candidates, 21.7% had a family/personal history or an anomalous laboratory result that required additional genetic counseling, stressing the importance of performing pre-donation genetic counseling in this population.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Genetic counseling and carrier screening in candidates for gamete donation at a Portuguese center

Soares¹,

Tkachenko²,

Fernandes³

et al. 2022

JBRA

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“…The disease-prone mutation prevalence is higher among European Caucasoids, with a carrier frequency estimate of 1/47, followed by, Asian Indians 1/52, Asians 1/59, "Hispanics" 1/68, and African Americans 1/72 [4]. In Venezuela, a carrier frequency of 1/72 has been reported among gamete donors from a fertility clinic in two sisters whose ancestors came from Spain and from Italy [5]. To date, copy number variation of both genes in the admixed Venezuelan populations is still unknown.…”

Section: Introductionmentioning

confidence: 99%

Spinal muscular atrophy in Venezuela: quantitative analysis of SMN1 and SMN2 genes

Yépez

Paradisi

Arias

2020

Egypt J Med Hum Genet

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Background: Spinal muscular atrophy (SMA) is mostly caused by homozygous deletions in the survival motor neuron 1 (SMN1) gene. SMN2, its paralogous gene, is a genetic modifier of the disease phenotype, and its copy number is correlated with SMA severity. The purpose of the study was to investigate the number of copies of the SMN1 and SMN2 genes in a Venezuelan population control sample and in patients with a presumptive diagnosis of SMA, besides estimating the frequency of mutation carriers in the population. Results: SMN1 and SMN2 gene copies were assessed in 49 Venezuelan dweller unrelated normal individuals and in 94 subjects from 29 families with a SMA presumptive diagnosis, using the quantitative PCR method. A SMN1 deletion carrier frequency of 0.01 and 0.163 of homozygous absence of the SMN2 gene were found in the Venezuelan control sample. Deletion of SMN1 exon 7 was confirmed in 15 families; the remaining 14 index cases had two SMN1 copies and a heterogeneous phenotype not attributable to SMN deletions. Based on clinical features of the index cases and the SMN2 copy number, a positive phenotype-genotype correlation was demonstrated. No disease geographical aggregation was found in the country. Conclusion: The frequency of carriers of the deletion of exon 7 in SMN1 in the Venezuelan control population was similar to that observed in populations worldwide, while the frequency of 0 copies of the SMN2 gene (16.3 %) seems to be relatively high. All these findings have pertinent implications for the diagnosis and genetic counseling on SMA in Venezuela.

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The use of expanded carrier screening of gamete donors

Payne

Skytte²,

Harper

2021

Human Reproduction

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STUDY QUESTION What are the sperm and egg donor rejection rates after expanded carrier screening (ECS)? SUMMARY ANSWER Using an ECS panel looking at 46/47 genes, 17.6% of donors were rejected. WHAT IS KNOWN ALREADY The use of ECS is becoming commonplace in assisted reproductive technology, including testing of egg and sperm donors. Most national guidelines recommend rejection of donors if they are carriers of a genetic disease. If the use of ECS increases, there will be a decline in the number of donors available. STUDY DESIGN, SIZE, DURATION A review of the current preconception ECS panels available to donors was carried out through an online search. The genetic testing results of donors from Cryos International were analysed to determine how many were rejected on the basis of the ECS. PARTICIPANTS/MATERIALS, SETTING, METHODS Data on gamete donors and their carrier status was provided by Cryos International, who screen donors using their own bespoke ECS panel. The ECS panels identified through the review were compared to the Cryos International panel and data. MAIN RESULTS AND THE ROLE OF CHANCE A total of 16 companies and 42 associated ECS panels were reviewed. There were a total of 2673 unique disorders covered by the panels examined, with a mean of 329 disorders screened. None of these disorders were common to all panels. Cryos International screen 46 disorders in males and 47 in females. From 883 candidate donors, 17.6% (155/883) were rejected based on their ECS result. Carriers of alpha-thalassaemia represented the largest proportion of those rejected (19.4%, 30/155), then spinal muscular atrophy (15.5%, 24/155) and cystic fibrosis (14.8%, 23/155). LIMITATIONS, REASONS FOR CAUTION Panel information was found on company websites and may not have been accurate. WIDER IMPLICATIONS OF THE FINDINGS This study highlights the need for consistent EU regulations and guidelines that allow genetic matching of gamete donors to their recipients, preventing the need to reject donors who are known carriers. A larger ECS panel would be most beneficial; however, this would not be viable without matching of donors and recipients. STUDY FUNDING/COMPETING INTEREST(S) No specific funding was obtained. J.C.H. is the founder of Global Women Connected, a platform to discuss women’s health issues and the Embryology and PGD Academy, who deliver education in clinical embryology. She has been paid to give a lecture by Cryos in 2019. A-B.S. is an employee of Cryos International. TRIAL REGISTRATION NUMBER N/A

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Expanded carrier screening in gamete donors of Venezuela

Cited by 3 publications

References 18 publications

Genetic counseling and carrier screening in candidates for gamete donation at a Portuguese center

Genetic counseling and carrier screening in candidates for gamete donation at a Portuguese center

Spinal muscular atrophy in Venezuela: quantitative analysis of SMN1 and SMN2 genes

The use of expanded carrier screening of gamete donors

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