Missing Brain Cells in Baby Boy Opens Doors to New Discoveries

Some parts of the baby’s brain stuck out at odd angles, others were too large and some did not develop.

The brain is a complex organ and the mutation in one of its gene can have far-reaching consequences. This is precisely what happened in the case of a young boy in the US whose brain was missing a set of cells called microglia because of the mutation of gene CSF1R. According to the report by The Atlantic it wasn’t anything like what the doctors had seen before.

The rare occurrence was caused by the inheritance of two faulty copies of the same gene, one inherited from each parent who both carried the rare gene since they’re cousins. The presence of the mutation in the parents also left them prone to the disorder.

Researchers are now realising that microglia is responsible for directing and influencing brain development.

However it has often been ignored since it’s not a neuron. This is despite it constituting 10 percent of the brain cells. In this particular case, the report pointed out, when microglia was missing, the neurons filled the baby’s skull, but their locations and connections were incorrect.

This also led to physical deformations in the brain where some parts stuck out at odd angles, others were too large and some did not develop. After ten months, the baby died of consequent problems.

This was perhaps the first time such a case was formally observed in humans. Previously scientists have attempted to observe the effects of the absence of microglia in animals. It was noticed in mice that the absence of microglia causes disorganised patterns in the brain.

However, the doctors were surprised to note the absence in a human and termed it “absolutely remarkable”. The boy’s case was severe since he had two copies of the faulty CSF1R gene - the presence of just one leads to a brain disorder (adult-onset leukoencephalopathy with axonal spheroids and pigmented glia) in adults linked with memory loss and dementia in early 40s. This particular case can potentially hold answers to several questions regarding the human brain.