Untreated Woman with SMA Type 3 Gives Birth to Two Healthy Children

Marta Figueiredo, PhD avatar

by Marta Figueiredo, PhD |

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Note: This story was updated Feb. 14, 2022, to clarify that this was a case of two successful pregnancies in the same woman, not that it was only the second-known such case in this population.

A 28-year-old Indonesian woman with spinal muscular atrophy (SMA) type 3 who never used any disease-modifying treatment gave birth to her second healthy child with the help of a multidisciplinary team, scientists reported.

This represents a rare case of successful pregnancy, not once but twice, in a previously untreated woman with a milder type of SMA. It also highlights the importance of a multidisciplinary team closely monitoring and managing such pregnancy to improve outcomes for both the mother and child, researchers noted.

The case study, “Managing pregnancy in a spinal muscular atrophy type III patient in Indonesia: a case report,” was published in the Journal of Medical Case Reports.

SMA is a progressive neuromuscular disease mostly caused by the loss of exon 7 in both copies of the SMN1 gene — one from the mother and one from the father. Exons are the sections of a gene that contain the information to generate proteins.

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While the disease “can be screened for in newborns, and even confirmed earlier genetically, this remains difficult in Third World countries such as Indonesia,” where genetic testing for SMA is not widely available or covered by the national health insurance, the researchers wrote.

Given SMA’s characteristic muscle weakness, bone deformities, and lung impairment, pregnancy in women with the disease can be classified as high risk. Several complications are known, including premature delivery (prior to 37 weeks of gestation), miscarriage, poor fetal growth, and maternal back pain.

Data on pregnancy management and successful deliveries among these patients are limited, being mainly restricted to individual case studies.

A team of researchers at Gadjah Mada University’s Faculty of Medicine, Public Health, and Nursing described the case of a 28-year-old Indonesian woman with SMA type 3 who successfully delivered two healthy children despite not being on disease-specific treatment.

The woman had been born prematurely at 32 weeks of gestation and achieved the ability to walk independently after her second birthday. At age 8 she started to stumble and lose balance while walking, suggesting SMA.

Her symptoms and age at symptom onset were consistent with SMA type 3, a milder form of the disease, but no genetic testing was then available to confirm the diagnosis.

She underwent physical and occupational therapy in a district hospital for one year, but her rural family had to stop the therapy due to financial difficulties and the hospital’s distance from the child’s home. Her disease subsequently progressed, and at 12 years old, she could no longer walk unaided, started using a wheelchair, and stopped going to school.

While three disease-modifying therapies for SMA have been approved in several countries since late 2016, none is available in Indonesia.

She was married at 25 and became pregnant shortly after. Her daughter was born prematurely at 32 weeks of gestation through cesarean section, and to date has no signs of muscle weakness.

For her second pregnancy, the woman was referred early to the researchers’ hospital to receive care involving obstetric, neurology, pediatric, and anesthesiology department teams.

Physical examination showed that she had severe scoliosis (an abnormal sideways curvature of the spine) and poorer muscle tone in her upper and lower extremities. Neuromuscular tests revealed nerve damage consistent with SMA.

Genetic testing for SMA, available at that institution since 2018, confirmed the absence of exon 7 in both her SMN1 gene copies, but not in her daughter, who was a carrier. Carriers, people with one mutated SMN1 copy, do not develop the disease but can pass the faulty gene to their children.

Neither analyses of the number of “backup” SMN2 gene copies, which helps to determine SMA severity and type, nor prenatal genetic testing were readily available at the hospital, so the woman’s SMA type remained unconfirmed and it was unclear whether had unborn baby had the disease.

After genetic counseling, the woman and her family decided to continue the pregnancy.

Her doctors analyzed three previous reports of pregnancy management in women with SMA to prepare to manage her pregnancy and delivery. A cesarean section was schedule for 38 weeks of gestation to prevent premature birth and respiratory problems for the baby.

The team closely monitored the mother for any discomfort due to her deformities and the fetus for any signs of poor growth.

“Fortunately, no maternal and fetal factors appeared until 38 weeks when the caesarean section was planned for delivery,” the researchers wrote.

Genetic testing on her second child, a boy, showed that he like his older sister was a carrier of the disease. He, too, had no evidence of muscular weakness.

This case described a woman with SMA type 3 “who managed to survive, have a reproductively active life, and gave birth to two healthy children (carriers) without any specific medications for her condition,” the scientists wrote.

“Genetic testing of spinal muscular atrophy and the collaborative management of this patient allowed the clinical decision making and genetic counseling throughout her pregnancy and delivery,” they added.

They stressed that “managing pregnancy in a patient with spinal muscular atrophy should be performed collaboratively” to “maximize the outcomes, both for the mother and her baby.”

An “ideal team should include an obstetrician, neurologist, neonatologist, geneticist, anesthesiologist, and respiratory specialist,” the scientists added.