Pediatric Genetics

Galatosemia

Babies born with this condition can’t process a sugar called galactose, which is found in milk. This sugar builds up and becomes harmful, damaging organs like the liver, brain, eyes, and kidneys. It can cause symptoms such as vomiting, yellowing of the skin (jaundice), trouble feeding, and poor growth if not treated.

Lysosomal storage disorders

This is a group of rare conditions where the body doesn’t have certain enzymes (special proteins that help speed up chemical reactions). These enzymes normally break down waste from fats, sugars, and proteins inside cells. Without them, waste builds up and damages organs like the brain, heart, liver, and bones. Over time, this can lead to delays in development, changes in appearance, and physical or intellectual disabilities.

Medium-chain Acyl-CoA Dehydrogenase (MCAD) deficiency

This condition prevents a child from turning fat into energy properly. This becomes dangerous during times like illness or heavy activity because the body runs out of energy and blood sugar drops very low. This can lead to serious problems like seizures or coma if not treated.

Phenylketonuria (PKU)

This condition prevents the body from breaking down an amino acid called phenylalanine (Phe), leading to toxic buildup, especially in the brain, causing intellectual disability, seizures, and developmental issues if untreated.

These genetic disorders affect the functioning of the heart and cardiovascular system. Examples include:

Cardiomyopathy

This includes any disorder that damages or weakens the muscle tissue of the heart, causing it to enlarge, thicken, or stiffen.

Congenital heart defects

Structural problems with the heart or major blood vessels (aorta and pulmonary veins) that are present at birth, such as holes in heart walls, heart valves that don’t seal properly, or underdeveloped heart chambers.

Irregular heartbeat (arrhythmia)

This includes any condition that affects the heart’s electrical system and causes your child’s heart to beat too fast, too slow, or in an irregular pattern.

Long QT Syndrome

Children with this arrhythmia condition may experience short periods of rapid and irregular heartbeats, which may induce fainting, heart palpitations, and other symptoms.

Humans typically have 23 pairs of chromosomes, which are the packages in which a person’s genetic information is stored. When these disorders are present, they typically occur when one or more chromosomes are duplicated, missing, or have structural abnormalities. They include:

Down syndrome

Children with this condition are born with an extra copy of chromosome 21. Common symptoms include mild-to-moderate intellectual disability, developmental delays (such as taking longer than most kids to learn how to crawl, talk, and walk), and certain facial features (such as a flattened face and upward-slanting eyes).

Turner syndrome

This condition affects genetic females who are born with one X chromosome (girls normally have two) partially or fully missing. Most girls with Turner syndrome will experience slowed growth, delayed or stalled puberty, and infertility unless they receive hormone therapy and fertility treatments at the appropriate times. Other symptoms can vary widely, and can be barely noticeable to more severe (such as heart defects).

This is a broad category of conditions which include any abnormalities with the construction or function of your child’s body, which are present at birth.

Cleft lip and cleft palate

During fetal development the upper lip, roof of the mouth (palate), or both don’t fully come together, leaving a gap or hole.

Congenital hearing loss

Hearing loss in newborns is often the result of a genetic condition or cause, such as structural defects in the outer or inner ear, nerve problems, or other factors.

Limb anomalies

Any of the hands, arms, feet, or legs are not fully developed, formed differently, or missing at birth.

These genetic conditions result in abnormal growth patterns in various parts of your child’s body. Examples include:

Short stature and growth restriction

Certain genetic disorders may cause children to grow more slowly than expected and be much shorter than their peers. This may even begin in the womb (intrauterine growth restriction) and can occur alongside other health problems.

Overgrowth syndromes

These disorders cause excessive growth in children, both before and after birth. This growth might affect their entire body or only certain areas (for example, on one side of the body) or tissues (such as bones or blood vessels).

Skeletal dysplasia

Disorders that cause abnormal growth and development of bones, joints, and cartilage. Examples include achondroplasia (very short limb growth) and osteogenesis imperfecta (brittle bones).

These conditions affect the way the brain and central nervous system develop, with symptoms usually appearing before birth or in early childhood. They are often at least partially influenced by genetic factors. Examples include:

Autism spectrum disorder

This condition affects how children perceive and interact with the world. Common signs include difficulty with language and social interactions, limited interests, repetitive behaviors, and sensory sensitivity (such as hypersensitivity to sound).

Developmental delays

This refers to a child failing to develop certain skills (such as walking, talking, or fine motor control) by the time most other kids do.

Fetal alcohol spectrum disorders

Exposure to alcohol while still in the womb can change how certain genes in a child’s body function — for example, by producing more or less of a certain protein than normal. It can lead to many possible symptoms, including intellectual disabilities, low body weight, and certain facial features.

Intellectual disability

These conditions prevent a child from developing core mental abilities, such as the capacity to use logic or think abstractly. This in turn can hinder or delay their ability to learn everyday life skills.

Neurological conditions include any disorder of the nervous system — including the brain, spinal cord, or peripheral nerves. Neuromuscular conditions specifically affect the peripheral nervous system, and in particular the way that motor nerves interact with muscle fibers to control movement. Examples include:

Epilepsy

This condition causes brief, reoccurring seizures, which are surges of electrical activity in the brain. Seizure symptoms vary from child to child but may include disorientation and confusion, jerking motions, or loss of consciousness.

Hypertonia

Children are born with too much muscle tone, which results in muscles that are stiff and inflexible and can make it difficult for kids to move their arms, legs, and neck. Involuntary muscle twitches or jerking is also possible.

Hypotonia

Children are born with too little muscle tone. Babies born with this condition may struggle to hold their head up or feel limp and droopy when held, and they may have difficulty with feeding. Development of other motor skills (such as sitting, crawling, and walking) may be delayed.

Muscular dystrophy

Diseases that cause muscles to lose mass and become gradually weaker over time. Symptoms often begin in early childhood.

These conditions are caused by abnormal mutations in a specific gene. Humans have around 20,000 genes, which are sequences of DNA that determine a person’s traits and how their body functions. Most children with single-gene disorders inherit the condition, meaning they received an abnormal copy of the gene from one or both parents (who may or may not have the condition themselves). Examples include:

Achondroplasia

This growth disorder results in abnormally short arms and legs. It is the most common cause of dwarfism.

Charcot-Marie-Tooth disease

Children with this condition typically experience loss of feeling and muscle weakness in the hands and feet due to peripheral nerve damage. Symptoms usually become noticeable during adolescence or early adulthood and slowly worsen over time.

Marfan syndrome

Children with this condition tend to be disproportionately tall and skinny with long limbs and fingers. They may develop other symptoms including hyperflexible joints, a curved spine, vision problems, and heart problems.

Noonan syndrome

This can be caused by a defect in one of the genes involved in regulating cellular division and growth. Symptoms vary but can include abnormal facial features (which tend to be most apparent during infancy but become more normal with age), short height, heart disease, increased bruising and bleeding, and learning delays.

Osteogenesis imperfecta (brittle bone disease)

Children with this condition have soft bones that are more prone to fracturing and may experience other symptoms including bone deformities and muscle weakness.

Spinocerebellar ataxia

This disorder affects a person’s ability to coordinate physical movement, which may result in balance issues, unsteady walking, slurred speech, or other challenges. Symptoms can begin at any time of childhood or adulthood and worsen over time.