Infant milestones are used by pediatricians and parents as a way to follow an infant's progress. Failure to reach milestones is called a developmental delay. In some cases, the delay is temporary and a baby will catch up, according to the University of Michigan Health System. In other cases, a delay is due to a disorder, something that alters the normal functioning of a baby's body. Parents are often the first to recognize a lag in reaching milestones. Contact your infant's pediatrician if you're ever concerned about his development.
Sometimes parents carry the gene for a disorder that plays a role in developmental delays, even if neither has the condition. These diseases are the result of gene mutations that alter a baby's DNA. Fragile X is one of the most common in males, notes the Duval County Medical Society. Down syndrome, Prader-Willi syndrome, Isodicentric 15 and Angelman syndrome are others that occur when a baby's chromosomes don't develop properly. They affect both males and females. These disorders cause delays in speech and language, cognitive development and physical milestones, such as walking and sitting.
A metabolic disorder involves how your baby's body processes food. In some cases it causes nutritional deficiencies and in other cases the disorder results in a buildup of a nutrient due to a missing enzyme. This can affect how a baby's brain works, which can impact your baby's physical milestones as well as those that deal with vision, sucking, swallowing and reflexes, according to the Dana Foundation. They can also impact cognition. Disorders that effect metabolism in infants include Zellweger’s syndrome, Smith-Lemli-Opitz syndrome, phenylketonuria, hypothyroidism, galactosemia and maple syrup urine disease. Some of these disorders are tested for at birth, while you'll have to request testing for others, especially if they run in your family.
Autism spectrum disorders can cause developmental delays that range in severity from mild to severe. They can appear in infancy or during the toddler years and result in delays of speech and language, social interaction and age-appropriate play, according to the Help Guide website. Classic autism, Rett syndrome, childhood disintegrative disorder and pervasive developmental disorder are those that fall on the autism spectrum.
Sometimes a brain disorder is present in infants. When the brain doesn't develop properly or undergoes some form of trauma, developmental delays often occur. This includes cognitive, physical, social, visual and hearing delays, though the symptoms range from mild to severe depending on the disorder and its severity. Some of these neurological disorders are cerebral palsy, central auditory processing disorder, expressive language disorder, Landau-Kleffner syndrome, learning disabilities and neural tube disorders such as spina bifida. In some cases, the disorder isn't recognized until later childhood, even though it might have been present at birth.