Our patient, a 38-year-old man, had suffered all his life from the skeletal disease "Hereditary Multiple Osteochondromas" (HMO). The condition had led to multiple operations to correct many recurrent bone deformities. He was the only member in his family to be affected.
The patient and his wife dreamt of having children but could not envision transmitting the disease to a child. Their best option was preimplantation genetic testing (PGT), allowing impregnation with an unaffected embryo.
Finding the root cause
The couple sought for a genetic diagnosis by gene sequencing from a diagnostic laboratory to identify the mutation behind the disease. Unfortunately, the laboratory could not find the mutation. The couple was told that PGT would be impossible.
As their last hope of being able to conceive a healthy child, they went for a second opinion to an in vitro fertilisation (IVF) clinic specialised in PGT. The clinician contacted SYNLAB Genetics to ask if further testing could provide any hope for the couple.
“Based on the patient's history and knowledge of the causes of HMO, we performed a second, more sensitive genetic test. This revealed that the patient carried a deletion of almost all the "EXT2" gene; such a gene deletion is rare but a known cause of HMO, present in 2-3% of patients”, explains Dr Giuditta Filippini, Head of Reproductive Genetics at SYNLAB Switzerland.
The test also showed that the mutation was "de novo", as in 10% of patients, indicating that it was not present in our patient’s parents.
A glimmer of hope
The identification of the mutation causing the patient’s disease meant that the couple was finally able to undergo IVF and PGT in the hope of having a child without the disease. To allow PGT, it was necessary to test 50 individual sperm cells to distinguish those carrying or not carrying the EXT2 mutation.
The first IVF cycle led to the generation of five embryos. Diagnosis with PGT revealed that three embryos carried the healthy copy of the EXT2 gene, and two had the mutation. One of the healthy embryos was transferred to the mother's uterus, and 9 months later a healthy baby was born.
Dr Filippini is happy to share the results and the outcome that defied the odds. “The IVF specialist collaborating with us at SYNLAB was able to help her patients achieve their dream of having a child, without the fear of transmitting the genetic disease.”
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