Sperm Bank

All our donors, who are assigned without genetic matching, must pass a basic screening for recessive diseases, including those recommended by the Spanish Fertility Society, as they are the most frequent in this region. The recessive diseases studied are the following:

Scientific studies estimate that most healthy people carry several mutations. In most cases, these genetic mutations show no symptoms, as an autosomal recessive genetic disease requires both inherited copies of the gene to be mutated.

Donors undergo genetic testing to determine their carrier status for autosomal recessive mutations. This allows selecting an ideal donor who does not share mutations with the recipient couple, minimizing the risk of the disease in their children.

Performing a genetic test such as the “Next Carrier Test” and selecting a donor by doing a genetic matching, provides with valuable information to know the status of carrier of genetic mutations that could not be suspected with a medical evaluation or family history. By performing it and comparing it with the genetic information of the other gamete that will participate in assisted reproduction therapy, the risk of having children with a genetic disease is minimized.

Because it analyzes ALL pathogenic and likely pathogenic variants in more than 2,100 genes responsible for autosomal recessive diseases.

Genetic screening, as we know it so far, is based on genetically testing and discarding those donors who are carriers of pathogenic and likely pathogenic variants of recessive monogenic diseases, which are serious and prevalent in our population. This way, we can reduce the risk of children being born with these diseases in treatments using donor gametes without genetic matching. Traditionally, this has been done and the difference between some gamete banks and others has been the number of diseases included in this screening.

Our genetic screening for sperm donors includes, in addition to the genes recommended by the SEF (Spanish Fertility Society), 7 other genes associated with recessive pathologies that are more prevalent in our environment (Mediterranean area of Europe).

The Carrier Genetic Test will give us information about a person’s carrier status, specially, which genes they have mutations in. In this case, we are referring to genes related to monogenic recessive diseases. There are currently numerous tests on the market that study more than 150 diseases or genes. To do this, they also use different techniques, such as Microarrays or the most recent NGS.

The Genetic Suitability Study involves using carrier tests of two individuals of different sexes and analyzing the coincidences. This will provide information on the risk of the offspring developing the various diseases being studied. In cases of non-coincidence, there will be a risk of having healthy carrier children, and in the case of coincidence, of having sick children.

Every cell in our body contains structures called chromosomes in which genetic information is stored. This information determines how we look and controls the development of all the organs in our body, such as the brain, heart, or kidneys. Most of the cells in our body contain 46 chromosomes, organized into 23 pairs, each consisting of one chromosome from the father and the other from the mother. The first 22 pairs are the same in males and females and are called autosomes, while the 23rd pair is made up of the sex chromosomes, which are called XX in females and XY in males.

Chromosomes contain genetic information packaged in the form of genes. There are more than 20,000 genes in the nucleus of every cell in our body. Each gene has one or more specific functions, but the function of many of the genes is still unknown. We have two copies (alleles) of each gene, one on each chromosome inherited from our parents, except for genes found on the sex chromosomes, with a single copy in males. Genetic diseases occur when one or more genes have an alteration (mutation). This dysfunction may be caused by a missing piece of gene or because the information is altered. Knowing the alteration that causes the disease can be important to make a correct diagnosis to the patient and family members. An alteration of a gene may appear spontaneously (de novo) in an individual, or be inherited from one or both parents. It is important to know that all people have alterations in some of our genes that usually go unnoticed, and only in certain circumstances do some of them cause diseases.

Autosomal recessive diseases occur when two mutated copies (or alleles) of the same gene are inherited. To do this, both the father and the mother must be carriers of the disease, that is, they both have an altered copy of the gene and that, by chance, both have passed the altered copy to their offspring. A carrier of a genetic mutation that causes a recessive disease does not manifest the symptoms of the disease and, in fact, all people are carriers of different mutations in recessive genes, without this leading to any clinical manifestation.

In the case of X-linked recessive diseases, the causative gene is located on this sex chromosome. 50% of the offspring of a carrier mother will receive the mutated copy of the gene. The effects of this mutated copy will be very different if a boy or a girl is conceived. While male offspring who receive a mutated copy of the gene will be affected and manifest the disease, girls with a single mutated copy do not usually present clinical manifestations, and will be healthy carriers (although due to the phenomenon called X chromosome inactivation, the presence of symptoms cannot be totally ruled out).

Genetic matching allows comparing the genetic information of the donor with that of the female recipient or donor of oocytes in order to avoid the transmission of recessive monogenic diseases.

The results of our donors are compared with the similar genetic study carried out on the recipient woman. A suitable donor is then selected, ensuring that the donor and the recipient woman do not share mutations in the same genes.

Our donors undergo thorough genetic analysis using Next-Generation Sequencing (NGS), covering a spectrum of 307 to 2128 genes. This includes scrutiny of variants prevalent in the Mediterranean region, ensuring comprehensive genetic screening.The ideal genetic matching is one that offers the maximum possibility of reducing the reproductive risk for the diseases included in the carrier study. This is achieved when both individuals providing the gametes have performed the same carrier test.

Many centers carry out carrier tests that are different from the one we carry out on our bank’s donors. In these cases, due to test incompatibility, the assignment will be carried out in such a way that the donor of our bank must have a report with a negative result (not a carrier of pathogenic variants) in the genes in which the recipient/donor of oocytes has been indentified as a carrier in the report provided by the requesting center.

Therefore, the genes to be taken into account for the matching will be defined by the genes that present variants in the test sent by the center in question. The rest of the genes not included in the test of the requesting center will not be taken into account for the preparation of the matching.

When we make an assignment through genetic matching, the risk of conceiving a child with the diseases studied in the genetic study carried out on the patient or oocyte donor is considerably reduced. However, this risk will never be zero. This is because there are technical limitations in the genetic tests of carriers that do not allow the analysis of some regions that are difficult to sequence in the genome or do not allow the detection of some genetic abnormalities for which they are necessary other specific techniques.

Therefore, the risk is not cancelled out, but it will be considerably reduced.