- Microcephaly is a condition in which a baby’s head is much smaller than normal.
- Most children with microcephaly also have a small brain, poor motor function, poor speech, and abnormal facial features, and are intellectually disabled.
- Researchers believe the roots of the condition lie in the peak phase of brain development in the embryo — when the cells that eventually become neurons fail to divide normally.
- Clinicians can diagnose microcephaly before the baby is born using foetal ultrasound and magnetic resonance imaging.
- Recent research by Chinese University reinforced the SASS6 gene’s role in causing microcephaly.
- These genes contain instructions for cells to make structures called centrioles.
- 70% or more of cases of congenital microcephaly seen in the clinic come from consanguineous marriages.
- These are marriages between closely related individuals, such as between uncle and niece or between first cousins.
- Consanguinity increases the risk of an individual inheriting a mutated copy of a gene from both parents.
- When researchers suppressed the SASS6 gene in roundworm C. elegans embryos, they found that the cells failed to assemble new centrioles, resulting in arrested development.
- After studying a family of four members who had microcephaly, researchers found the mutation (Ile62Thr) correlated with microcephaly.
- Humans with the Ile62Thr mutation can survive but suffer brain deficits due to impaired centriole function, leading to microcephaly and intellectual disability. Neurons are particularly sensitive to centriole defects.
- The amino acid isoleucine in the SASS6 gene had been replaced by threonine. Thus, it is named Ile62Thr.
Dig Deeper: Read about genetic disorders like Down’s Syndrome, Klinefelter’s Syndrome and Turner’s Syndrome.
