Ask the Expert Series: How do genetic factors affect brain development?

Some babies with brain development problems may exhibit tremors or muscle spasms or even develop paralysis in certain parts of the body. Extreme fatigue can also be a sign of brain damage. As a baby grows, brain damage may cause delayed physical development. A baby may be slow to crawl, sit up, stand up, and walk. Infant brain damage symptoms are varied and diverse. For some children, the signs may not even show up for months or years, or if they do may not be obvious enough to lead to a diagnosis

The first stages of brain development are strongly affected by genetic factors, however, genes do not design the brain completely. Instead, when and where genes are used is fine-tuned according to the input they receive from the environment – this happens even during pregnancy when maternal nutrition and stress can influence the early phases of brain architecture. These gene-environment relations allow for each child to adapt to their surroundings more readily and more quickly than they could if genes alone determined the brain’s wiring.

Both genetics and nutrition will contribute to child intelligence. Studies show that individual differences in human intelligence can largely (50%–80%) be explained by genetic influences making intelligence one of the most heritable traits. On the other hand, scientists also found that infants who ate healthy foods had higher IQ scores by age 8 than those who ate less healthy foods. Thus, both genetics and nutrition are equally important.

According to studies on association of age and genetics on intelligence, the heritability of intelligence increases linearly, from (approximately) 20% in infancy to 40% in adolescence, and to 60% in adulthood. Some evidence suggests that heritability might increase to as much as 80% in later adulthood but then decline to about 60% after age 80. So the answer is yes.

Like most aspects of human behavior and cognition, intelligence is a complex trait that is influenced by both genetic and environmental factors.

Some babies have anencephaly because of a change in their genes or chromosomes. Anencephaly might also be caused by a combination of genes and other factors, such as the things the mother comes in contact with in the environment or what the mother eats or drinks, or certain medicines she uses during pregnancy.

Play ideas for encouraging newborn cognitive development. Talk to your baby often, hold your baby, and make eye contact. Read with your baby, recite nursery rhymes, or sing songs. Repeating the same song, rhyme or story isn't boring for babies – repetition is one of the ways they learn. Make faces with your baby. Eggs, salmon, lean meat and dairy - these are some foods that are good for a child's brain development.

Genetic factors are estimated to contribute 40 to 80 percent of autism spectrum disorder risk. The risk from gene variants combined with environmental risk factors, such as parental age, birth complications, and others that have not been identified, determine an individual's risk of developing this complex condition. Thus, autism is partially determined by genetics.

According to study, very premature children (

Signs of giftedness can appear as early as infancy and continue during the toddler and preschool years. Testing for giftedness and high IQ, however, usually takes place around age 5.