Sixteen-month-old Alainah Therrien of Cape Cod was probably never exposed to the Zika virus. But she has a smaller-than-normal head and was diagnosed with microcephaly even before she was born.
“I was told when I was 24 weeks pregnant that we would have a daughter who was mentally retarded,” recounts her mother Melissa.
Melissa’s labor was induced at 36 weeks because Alainah had stopped growing. After Alainah was born, a tiny 5 pounds, Melissa saw the word microcephaly for the first time on the bottom of a medical form. The pediatrician didn’t know what microcephaly was, but thought perhaps the bones of Alainah’s skull had fused together prematurely. If so, she would need neurosurgery.
“I’m going to refer you to a neurosurgeon in Boston,” she told Melissa.
Alainah’s skull was fine, and she did not need neurosurgery. Instead, she began seeing neurologists Drs. Jeffrey Neil and Ganeshwaran Mochida at Boston Children’s Hospital. Mochida, a specialist in microcephaly, brought Alainah into Boston Children’s Brain Development and Genetics clinic, which sees children with a variety of brain malformations and seeks to discover the causes.
Alainah’s developmental delay
“We didn’t know if anything was really wrong at first,” says Melissa. “As Alainah started to get older, she seemed a little delayed, so we began early intervention at 3 months. Right now, at 16 months, her development is at a 9-, 10- or 11-month mark.”
“She’s bright and can use her body well to communicate with people,” says Melissa. “If you didn’t know she has microcephaly, you would just see a tiny little girl.”
But Alainah’s sensory delays and self-injurious behaviors, such as pulling her own hair and repetitively hitting herself on the head, concern her parents.
Knowing the cause of microcephaly is important in predicting how a child will do, says Mochida, because the term covers many different diseases.
Some forms of microcephaly are associated with severe developmental delay or a high risk for seizures; some are not. Some forms can impair motor function or affect other organs in the body, with complications that need to be watched for. For example, microcephaly linked to Zika and certain other prenatal infections sometimes comes with vision and hearing problems.
If you didn’t know she has microcephaly, you would just see a tiny little girl.” In Alainah’s case, the cause remains to be found. “We know it’s not infection, we know it’s genetic,” says Melissa.
“Without a specific diagnosis, we often have a very limited ability to predict how a child will do, particularly in the first year of life,” says Mochida. “But through repeat neurological examinations, we can gradually get a better picture. If we know the underlying condition, we can provide the best care.”
Diagnostic testing for microcephaly
Alainah has had some readily available genetic tests, but these showed nothing definitive, so her parents agreed to enroll her in a research study to look more deeply into the cause of her microcephaly. Alainah, her parents and her unaffected 6-year-old sister will provide DNA samples for sequencing, joining some 300 other families with microcephaly.
“We will look at Alainah’s genome to see any change that she has,” says Mochida. “Several hundred genes are already linked to microcephaly, but we believe quite a few genes are yet to be discovered. For some rare genes we’ve found more recently, the only way to know the full spectrum of disease is to diagnose and follow as many children with mutations in that gene as possible.”
It can take years to find enough children with a given mutation to study: In the U.S., the total number of infants with microcephaly is estimated to range from 2 to 12 babies per 10,000 live births.
“MRI tells us the structure of the brain, but not how the brain is functioning,” says Mochida. “Sometimes we see strikingly abnormal MRIs, but the child is doing much better than you would expect.”
Nor does head size always predict how a child will do. “There is definitely some correlation, but more important is the cause of the microcephaly,” says Mochida. “There are conditions that can cause a quite small head size but have reasonably good neurologic outcomes. Or microcephaly can be relatively mild but intellectual disability can be quite severe.”
While the Therriens wait for a diagnosis, they are giving Alainah the best chance possible through early interventions including physical and occupational therapy and, soon, speech therapy. Alainah is also being followed by Dr. Neil in the Department of Neurology.
“If we have something come up, Neurology will fit us right in or talk to us over the phone,” says Melissa. “We’re very connected, and I like that.”
Although in most cases there is no cure for microcephaly, with the exception of certain treatable metabolic disorders, Mochida urges families to intervene early and seek specialty care, as the Therriens have. While a small brain may not catch up to normal size, it can still generate new connections between neurons. “Early intervention is key in maximizing the child’s potential and minimizing complications,” he says. “Children’s brains are very plastic and can adapt in ways that adult brains cannot.”
Melissa hopes to launch a family support organization for microcephaly and is raising seed money through the crowdfunding site GoFundMe. “We completely understand what families are going through and how they may feel,” she says.
Learn more about the Brain Development and Genetics clinic at Boston Children’s.