OBJECTIVE: To develop and validate a simple and reliable single-cell analysis protocol for the preimplantation genetic diagnosis (PGD) of spinal muscular atrophy (SMA). DESIGN: Molecular tests based on specific enzymatic digestion have already been described for SMA diagnosis. We modified the amplified DNA fragments so as to introduce a novel restriction site that provides an internal control for the completeness of the digestion. SETTING: The genetics and reproduction departments of two teaching hospitals. PATIENT(S): Six informed couples at risk of transmitting SMA. INTERVENTION(S): All patients underwent standard procedures associated with intracytoplasmic sperm injection. MAIN OUTCOME MEASURE(S): Improvement of SMA diagnostic efficiency and accuracy on single cell. RESULT(S): One hundred fifty lymphocytes were analyzed with our protocol. One hundred percent diagnostic accuracy was achieved from both homozygous normal and SMN1-deleted leukocytes. Successful molecular analysis was achieved for 36 of 42 biopsied embryos (86%). Twenty-five normal embryos were transferred, but no pregnancy was achieved. CONCLUSION(S): We developed an improved protocol for PGD of SMA that is simple, robust, and accurate; unfortunately, no pregnancies were achieved for any of the six patients who have undergone PGD in the program thus far.
OBJECTIVE: To develop and validate a simple and reliable single-cell analysis protocol for the preimplantation genetic diagnosis (PGD) of spinal muscular atrophy (SMA). DESIGN: Molecular tests based on specific enzymatic digestion have already been described for SMA diagnosis. We modified the amplified DNA fragments so as to introduce a novel restriction site that provides an internal control for the completeness of the digestion. SETTING: The genetics and reproduction departments of two teaching hospitals. PATIENT(S): Six informed couples at risk of transmitting SMA. INTERVENTION(S): All patients underwent standard procedures associated with intracytoplasmic sperm injection. MAIN OUTCOME MEASURE(S): Improvement of SMA diagnostic efficiency and accuracy on single cell. RESULT(S): One hundred fifty lymphocytes were analyzed with our protocol. One hundred percent diagnostic accuracy was achieved from both homozygous normal and SMN1-deleted leukocytes. Successful molecular analysis was achieved for 36 of 42 biopsied embryos (86%). Twenty-five normal embryos were transferred, but no pregnancy was achieved. CONCLUSION(S): We developed an improved protocol for PGD of SMA that is simple, robust, and accurate; unfortunately, no pregnancies were achieved for any of the six patients who have undergone PGD in the program thus far.