Hemophilia, Inheritance and Assisted Reproduction Treatments

Hemophilia

Hemophilia is a disorder that prevents or significantly slows blood clotting. It is manifested through bleeding—internal or external—often caused spontaneously. There are two main components involved in blood coagulation: platelet function and plasma clotting factors. Hemophilia is currently incurable and typically requires lifelong replacement therapy adapted to the patient's needs.

Treatment Types for Hemophilia

• On-demand treatment: administration of clotting factor after the first symptoms or after a bleeding event.
• Prophylactic treatment: routine administration of clotting factor to prevent bleeding episodes.

Sources of Clotting Factor Concentrates

There are two ways to obtain clotting factor concentrates:

• Plasma-derived: purified and separated from donor blood.
• Recombinant: produced by recombinant technology and obtained with a higher degree of purity.

Inheritance of Hemophilia

Sex chromosomes determine sex in humans. The X chromosome is larger than the Y chromosome and contains many genes. The gene for producing certain clotting factors is located on the X chromosome; the Y chromosome does not contain that gene. Because of this, males (with one X chromosome) who inherit a defective clotting-factor gene on their X chromosome are typically affected, while females (with two X chromosomes) who carry a defective gene on one X chromosome are often carriers.

Antibiotic

An antibiotic is a substance produced by a microorganism that has the property of killing or inhibiting the growth of other microorganisms. Antibiotics are not effective against viruses.

Assisted Reproduction and Preimplantation Diagnosis

Assisted reproduction techniques, including preimplantation genetic diagnosis (PGD), can be used to help prevent the inheritance of certain genetic conditions in children.

PGD Procedure Summary

PGD involves the following steps:

1. Hormonal ovarian stimulation for the woman.
2. Oocyte (egg) retrieval by follicular aspiration.
3. In vitro fertilization (IVF) of the retrieved eggs.
4. The fertilized zygote is cultured until approximately the 8-cell stage.
5. A cell (or cells) from the pre-embryo is analyzed genetically and biochemically before implantation.

In Vitro Fertilization

In vitro fertilization (IVF) is an assisted reproduction technique performed in a laboratory in which one or more ova from the woman are combined with sperm. IVF can help when there are fertility problems. The typical steps are:

• Ovarian stimulation treatment.
• Follicular puncture to retrieve eggs.
• Insemination of eggs in the laboratory using semen from the partner or from a sperm bank, according to the couple's decision.
• Transfer of embryos into the woman's uterus.

The average pregnancy rate achieved is around 40% (rates vary by clinic, patient age and other factors).