Distal 18q-: Health Concerns

This page describes some of the most common health problems that have been reported in people with distal 18q-. It is important to remember that these concerns do not occur in everyone with distal 18q-. Also, we do not discuss treatment options or recommendations on this page. It is important that you speak with your team of healthcare providers to make a plan to check for and manage health concerns. In addition, the Chromosome 18 Clinical Research Center has developed Management Guidelines. These documents have more detailed information about the health problems seen in people with distal 18q-, including how frequently they occur. They also include specific recommendations about checking for health issues.

Lastly, it is important to understand that people with distal 18q- may develop health problems that are not listed on this page. As research on the chromosome 18 conditions continues, we will learn more about what to expect for people with distal 18q- and how to help them stay healthy and live productive, fulfilling lives.

Babies with distal 18q- may develop differently in the womb, leading to birth defects. Different types of heart defects have been reported in babies with distal 18q-. Foot abnormalities, such as rocker bottom foot and clubfoot, are also common. Babies with 18q- may also have an opening in the roof of their mouth, called a cleft palate. They may or may not also have a cleft lip.

Hernias have been reported in some newborns with distal 18q-. A hernia occurs when some organs, often the intestines, push outside of the abdomen into another part of the body. Both inguinal (involving the groin region) and umbilical hernias (involving the umbilical opening) have been seen in babies with distal 18q-.

Newborns with distal 18q- may have problems at or shortly after birth. They may have feeding difficulties. For example, they may have problems latching onto the breast or bottle. They may also have problems coordinating the suck-swallow motion that is required to nurse. Some infants may vomit frequently after eating. If they have a cleft or a high arched palate, they may have additional difficulties feeding.

Lastly, some infants with distal 18q- have breathing problems shortly after birth.

Infants with distal 18q- may also have jaundice. Jaundice is a build-up of bilirubin in the baby’s blood, leading to a yellowish color of the skin and eyes.

People with distal 18q- have a higher chance of having changes in their nervous and muscular systems. Many have low muscle tone (hypotonia).

Seizures are a fairly common concern in people with distal 18q-.

Almost everyone with distal 18q- has a decreased amount of myelin in the central nervous system. This is called dysmyelination and can only be identified with an MRI. Myelin is a substance that covers nerve cells similar to the way that plastic coating covers a wire in an electric cord. The myelin helps transmit electrical signals to and from the brain. At this point in time, we do not know if or how these changes in the amount of myelin affect a child’s development. We suspect that it slows an individual’s reaction time. For example, it might take a person with distal 18q- longer to understand an instruction or to respond to a question. Dysmyelination may also contribute to attention problems, anxiety, and depression.

People with distal 18q- frequently have vision problems. In particular, strabismus and nystagmus can be associated with distal 18q-. Strabismus occurs when the movements of the eyes are not coordinated with each other. This is frequently referred to as being “cross-eyed”. Nystagmus describes repetitive and uncontrolled movements of the eyes. In addition, near-sightedness is seen in some people with distal 18q-.

Children with distal 18q- have a higher likelihood of having hearing loss. There are two types of hearing loss. Conductive hearing loss describes hearing loss that is caused when there is an obstruction to the transmission of sound from the outer ear to the inner ear. People with distal 18q- often have narrow ear canals; some people’s ear canals are completely closed. This can lead to conductive hearing loss. Recurrent ear infections are another cause of conductive hearing loss.

The second type of hearing loss is called sensorineural hearing loss. This refers to a hearing loss that is caused by a change in the nerves that transmit signals from the ear to the brain.

People with distal 18q- may have conductive hearing loss, sensorineural hearing loss, or a combination of the two.

Babies and children with distal 18q- may have some problems with digestion. The most common digestive problem is reflux. This occurs when the stomach contents flow upwards. This can cause pain, irritability, and vomiting.

Males with distal 18q- may have some changes in the genital region. The testicles may not be fully descended (cryptorchidism). The opening of the urethra may not be at the end of the penis (hypospadias). The penis may turn downward (chordee).

Some people with distal 18q- may have kidney problems. This can affect both males and females. Vesicoureteral reflux frequently happens in people with distal 18q-. This occurs when urine flows from the bladder up towards the kidneys. This is known as vesicoureteral reflux and can lead to recurrent urinary tract infections and kidney damage. In addition, some people have structural changes in the kidney.

In addition to foot abnormalities that are present at birth, some people with distal 18q- may have flat feet or toes that overlap each other. Some develop an abnormal curvature of their spine (scoliosis or kyphosis). People with distal 18q- may have “bow-leggedness” (genu varum). All of these bone problems can affect the way they walk and may lead to gait abnormalities.

Children and adults with distal 18q- may have changes in their growth patterns. They are often small for their age. This is frequently due to growth hormone deficiency. Growth hormone deficiency has been reported frequently within the literature as well as by research participants at the Chromosome 18 Clinical Research Center.

Some people with distal 18q- have changes in their hormone levels. These include growth hormone deficiency (discussed above). Thyroid abnormalities are also fairly common in people with distal 18q-. Low thyroid is the most common thyroid change. Symptoms of low thyroid include fatigue, weight gain, and depression.

Low levels of IgA are found in some people with distal 18q-. IgA is a protein that helps fight off infections. People who have a low level of IgA are more likely to get infections and colds than those with normal levels of IgA.

Recently, we have also learned that people with distal 18q- seem to have a higher incidence of autoimmune conditions. Autoimmune conditions are a group of disorders that are caused when the immune system mistakenly attacks the body. Lupus, arthritis, and Sjogren syndrome have all been reported in people with distal 18q-.

We have learned that people with distal 18q- often develop anxiety and/or depression during adolescence.

People with distal 18q- may have facial features that are slightly different from other family members. These changes do not affect a child’s health or development. They are simply small differences that might be noted by a doctor. The middle of their face may look flat. Their eye openings may be short or slant upwards or downwards. They may have an extra fold of skin covering the corner of the eye. Their ears might be lower and look slightly different than a “typical” ear.

Although people with distal 18q- may have facial features in common with one another, it is important to remember that they also have features in common with their family members.

We are still collecting information about lifespan in individuals with distal 18q-. However, we know that people that are missing the TCF4 gene have a higher risk for early death. This group is often more complicated from both a medical and a developmental standpoint, and they are more susceptible to infections and other problems.