Down Syndrome: Causes, Symptoms, Diagnosis, & Treatment

Down Syndrome

Down syndrome is a chromosomal disorder that occurs in 1 in every 700 pregnancies in the U.S. and one in every one thousand live births on Guam. Down Syndrome is characterized by physical, mental and developmental ailments and an increased risk of many general diseases. While no treatment or prevention is available, screening can detect the abnormality. Educational resources and medical check ups can aid in improving the quality and duration of life for parents and individuals with Down syndrome. However, education and resources available to Guam are limited compared to those available in areas with incidence of Down syndrome in the U.S.

Down syndrome is considered the most common genetic form of mental retardation and is also the leading cause of many birth defects and other medical conditions that accompany the disorder. It is a chromosomal disorder caused by an error is cell division of chromosome 21. A non-afflicted person would have 23 genes in a cell grouped in chromosomes. A person should have a total of 46 chromosomes, with 23 coming from the mother and the other 23 coming from the father. Typically there are two copies of every gene, but in an individual with Down syndrome chromosome 21 divides abnormally resulting in an extra third copy and a total of 47 chromosomes. Down syndrome may result from any version of chromosome 21 that is considered extra, full or partial. There are three types of Down syndrome ranging from mild to severe.

Types of Down syndrome

Trisomy 21

Trisomy 21 or non-disjunction is the most common form of Down syndrome and accounts for ninety five percent of Down syndrome cases. It occurs in one out of every seven hundred and fifty live births, which increases in women after the age of 34. Trisomy 21 has a gender ratio of 3 males to 2 females. This specific form of Down syndrome is definitive before or during conception and can be tested and diagnosed during pregnancy.

Mosaic Down syndrome

Mosaic Down syndrome accounts for two percent of all cases. An individual with mosaic Down syndrome will have a mixture of cells with and without an extra full or partial copy of the chromosome 21. This is considered a rare form of Down syndrome and has similar characteristics of those with trisomy 21, however, a person with mosaic down syndrome may have less symptoms than a person with the more common form. It is noted that those with mosaic Down syndrome also have a generally higher IQ than individuals with other forms of Down syndrome.

Robertsonian translocation

The third type of Down syndrome is called Robertsonian translocation. Translocation is considered more as a contributing gene to down Syndrome than the actual affliction with Down syndrome. This happens when part of the chromosome 21 detaches and fuses with another chromosome. While this form of Down syndrome does not have any physical implications, this puts a person at a higher risk of having a child with Down syndrome. Other fertility problems such as infertility, miscarriages, or difficulties getting pregnant may be experienced with a person carrying the translocation.

Frequency of Down Syndrome

Down Syndrome occurs across the world in one in every seven hundred pregnancies on average. One in every one thousand live births on Guam is to babies with Down syndrome. This risk increases for mothers over the age of 35 and jumps to 12 in every 1000 pregnancies for women above 40. Some studies suggest that there may be a variation of prevalence between some racial groups, however this is not measured and recorded for records on Guam.

This table from the Centers for Disease Control and Prevention shows the Prevalence of Down Syndrome by Mother's Age. There seems to be very little variance between the age groups of less than twenty years of age to the twenty through forty years of age group and again through the twenty five through twenty nine years of age group. There is a slight but noticeable increase between the group of twenty five through twenty nine and the group of thirty through thirty four years of age. This puts the prevalence from about seven incidences for every ten thousand live births to about twenty in every ten thousand live births between the ages of twenty nine to thirty through thirty four, then the prevalence goes to roughly forty occurrences for every ten thousand live births in the ages group of thirty five through thirty nine. From this point in the chart shows the largest jump in occurrence from forty incidences for every ten thousand live births in the thirty five through thirty nine age group to a whopping one hundred and twenty occurrences for every ten thousand live births on the age group of forty years of age and over. This is a two hundred percent increase between the ages of thirty five through thirty nine and the age group of forty year and over.

Characteristics of Down Syndrome

Down Syndrome is characterized by obvious physical, mental and developmental implications and an increased risk of many general diseases. Physical associations may include an evocative face. This could include any of the following characteristics: microcephaly, short neck, brachycephaly, flat nose bridge, socket nostril, epicanthus, hypertelorism, upward slanting palpebral fissures, malformed teeth, eyes that are close together, frequently open mouth. Physical characteristics of the hands and feet may be short and broad, small stature and short neck, low muscle tone, protruding tongue, a deep crease in the center of the palm, flat feet, abnormalities on the 2nd and 5th fingers, and the first toe may be set apart by a gap from the rest. Skin may be dry with infections frequently around orifices.

Motor delays can be seen in an infant by the time the infant reaches mile stones like holding up the head at 6 months, sitting at a year, and taking first steps at 2 years. Mental retardation may not be seen immediately but will show eventually in other milestones, or lack of reaching milestones with language skills and memory. Older children with Down syndrome may show personality traits that are affectionate and cheerful. The child may even be playful and like to help with cleaning up.

Medical Concerns

Many medical concerns are associated with infants, children and adults with Down syndrome. These conditions can be more prevalent in individuals with Down syndrome compared to a person in the general population. According to the Down syndrome website, DSE, many Down syndrome individuals have:

• Congenital heart defects: forty seven percent with ten to fifteen percent of babies that require surgical intervention in the first few months of life. This procedure has a great impact on survival on eighty to ninety percent passed the age of five.
• Respiratory issues: most common in the first five years because they have pooper immune systems. Lung disease and pneumonia are commonly reported.
• Visual impairments: seventy percent are recorded to have eye concerns. Refractive errors and eye diseases. This increases in older individuals. Glasses are typically used for corrective and preventive measure. Cataracts are also reported in both children and adult groups.
• Infections: ear infections and hearing loss were detected using assessment tools, and hearing aids are used.
• Epilepsy: Anxiety, hyperventilation and panic attacks caused seizures and fainting although some were non epileptic.
• Hyperthyroidism: Screening for individuals with Down syndrome is recommended every 2 years for life. It is found to be more prevalent in the older population than in the youth.
• Alzheimer's disease: evident in almost all patients over 30 is dementia. Alzheimer's was observed in ten percent of age group forty through forty-nine and in twenty six percent of those aged fifty and up.
• Leukemia: Children with Down syndrome are more likely to develop cancer up to ten and twenty percent more than the general population. Appropriate cancer treatments have been successful in the case of Down syndrome patients.
• Oral concerns: oral health of children is less of a concern than those in adulthood with deteriorating periodontal health and dental loss, which may have been caused by fearfulness. This could be treated with anesthetics used for correction.

Medical specialists

It is important for healthy development of a child with Down syndrome to consult specialists to advise proper medical interventions to keep many of the medical conditions under control.

The Children's Hospital of Philadelphia suggests the following specialists for regular follow-ups:

• An orthopedic physician for any bone- and muscle-related issues, particularly to diagnose and manage instability of the cervical spine, hip instability and the possibility of hip dislocation.
• A cardiologist for any heart-related issues. An echocardiogram may be ordered to create pictures of your baby's heart to help diagnose or rule out heart defects.
• A pediatric audiologist, who is trained to identify, diagnose, treat and monitor hearing problems.
• A pediatric ophthalmologist (eye doctor), who can assess your child's vision and diagnosis and treat eye or vision problems.
• A pediatric endocrinologist for a thyroid function test. Thyroid hormones play an important role in your child's growth, development and metabolism. Thyroid levels are checked with a blood test.
• A geneticist for individual or family counseling.
• A pulmonologist for any breathing issues.
• A neurologist for any nerve and brain-related issues.
• Physical therapists and occupational therapists to expand your child's physical dexterity and skill.

Treatment

Screening

While no treatment or prevention is available for Down syndrome specifically, there are diagnostic screening tests to definitively identify a pregnancy of a developing fetus with Down syndrome. At eleven to fourteen weeks, nuchal translucency testing can be done on the tissue on the posterior neck of a developing fetus to measure the clear space in the folds. At fifteen to eighteen weeks, a triple screen or quadruple screen can measure the quantities of different substances in maternal blood. An integrated screen can combine first trimester blood tests and screening tests with the second trimester quadruple screening results, which can be done with or without the nuchal translucency. Cell-free DNA can analyze the DNA of the developing fetus found in the blood of the mother. From eighteen to twenty weeks, a genetic ultra sound can combine blood test results with the detailed ultra sound. This information was all found in the Medical News Today Newsletter.

Screening is both cost-effective and non-invasive. It helps to identify whether further tests are needed for a more accurate diagnostic test. A screening will only show if a mother is at a higher risk for having a child with Down syndrome and will not be able to detect if Down syndrome is present.

Diagnostic Tests

Diagnostic tests on the other hand are more accurate than screening to identify Down syndrome or even other medical conditions that may pose a risk for the developing agnostic test is invasive as the procedures are performed inside the uterus. The diagnostic test may increase the result of a miscarriage and may result in fetal injury ad preterm labor is at a higher risk as well. There are three types of diagnostic tests. The first is chronic villus sampling. This can be performed at eight to twelve weeks. In chorionic villus sampling, a small sample of the uterus is observed. The sample is obtained by inserting a needle into the cervix or the abdomen.

Another kind of diagnostic testing is called amniocentesis, which can be performed at 15 to 20 weeks according to the medical News Today Newsletter. The Moy clinic website describes further that amniocentesis removes fluid from the uterus for testing or treatment. The amniotic fluid contains fetal cells that can be used for genetic testing, fetal lung testing, and diagnosis of fetal infection, treatment, and paternity testing. Genetic amniocentesis for genetic testing involves testing the amniotic fluid from the amniotic sac and this is the method that is used for testing for Down syndrome. It is also used for other reasons already listed like fetal lung testing. This involves taking a sample of the amniotic fluid from the amniotic sac and testing that fluid to determine if a baby's lungs are mature enough for being born into the world. Using the amniotic fluid from the amniotic sac to be evaluated for an infection or illness can use amniocentesis to diagnose fetal infection. The fluid from the amniocentesis can also be used to evaluate how seriously a baby may be afflicted with anemia if the baby has Rh sensitization. Rh sensitization is an uncommon condition characterized by the maternal immune system producing antibodies that attack a specific protein on the outer surface of a developing fetus' blood cells. Amniocentesis can be used for treatment as well. If a mother has too much amniotic fluid in her amniotic sac she may have what is called polyhydramnios. Amniocentesis can be used in this case to drain her amniotic fluid from her amniotic sac and from her uterus. The last thing an amniocentesis can be used for is Paternity testing. An amniocentesis can obtain DNA of a developing fetus and have that DNA be compared to a potential father.

The last diagnostic test to be covered shortly is called the percutaneous umbilical blood sampling- also known as cordocentesis that can be performed at 20 weeks. This percutaneous umbilical blood sampling diagnostic prenatal test or cordocentesis, according to the Mayo Clinic online, is a thirty minute to sixty minute procedure in which a blood sample is extracted from the umbilical cord of the developing fetus. This percutaneous umbilical blood sampling (or cordocentesis) diagnostic test can be used to identify genetic disorder or any infections of the blood that may indicate a certain condition. This percutaneous umbilical blood sampling procedure or cordocentesis of the three procedures listed before is the most risky and as a result of its higher risk of loss of pregnancy is used the least between percutaneous umbilical blood sampling or cordocentesis, amniocentesis, and chronic villus sampling. Despite its higher risk of fetal loss, this percutaneous umbilical blood sampling procedure or cordocentesis may be used as a diagnostic test if the other diagnostic tests (amniocentesis, and chronic villus testing) are shown to be insufficient or inconclusive. This percutaneous umbilical blood sampling procedure or cordocentesis is typically used to identify or detect blood conditions like anemia or other conditions. If a mother uses the percutaneous umbilical blood sampling or cordocentesis procedure, she may be checking for a low amount of healthy red blood cells, or the mother may be using the percutaneous umbilical blood sampling or cordocentesis as a blood karyotyping for the developing fetus. This can be done in forty eight hours and sometimes results may be expected back more quickly than results from an amniocentesis diagnostic test or a chorionic villus sampling diagnostic test.

The Mayo Clinic online also lists some risks that are associated with percutaneous umbilical blood sampling or cordocentesis. The risks include fetal bleeding, cord hematoma, slowing of the fetus' heart rate, infection, loss of the pregnancy, and fetal-maternal bleeding. Fetal bleeding may c=occur wherever the needle was inserted into the umbilical cord. This problem is the most common issue with percutaneous umbilical blood sampling or cordocentesis. The fetal bleeding may even be life threatening. If so, and bleeding does occur in the fetus and threatens its' life a physician or caretaker may advise that the blood products of the fetus be replaced. Cord hematoma is another risk associated with percutaneous umbilical blood sampling or cordocentesis. This cord hematoma is a collection of the fetus' blood inside the cord. This cord hematoma may occur at the time of the cordocentesis or percutaneous umbilical blood sampling procedure or after the procedure is completed. Although this does not happen in all cases, some babies will not even show symptoms that a cord hematoma has happened or is happening. One way to detect a cord hematoma is observe a low heart rate of the fetus for a short period of time. This can ultimately go two ways. If the cord hematoma does not pose a risk and become stable then a care provider or physician may just recommend that the baby be under close surveillance. On the opposite spectrum if the cord hematoma shows a large risk then a caretaker or physician may make the order to perform an emergency cesarean section to spare the life of either the mother or the baby.

After any of these screening tests like nuchal translucency, triple screening, quadruple screening, integrated screening, cell-free DNA screening, and genetic ultrasound or diagnostic tests such as the chorionic villus sampling, amniocentesis, and the percutaneous umbilical blood sampling (or cordocentesis) prove that a fetus is diagnosed with Down syndrome, actions can be taken to prepare a mother and her family emotionally for the care that ill be needed to ensure the child survives passed its first year given the mother decides to continue with the pregnancy.

Healthy People 2020

Healthy people 2020 is a 10 year science based objective list that aims to improve the health status of all Americans.

On the Healthy people 2020 website, included in its overarching goals related to Down syndrome is:

• Attain high-quality, longer lives free of preventable disease, disability, injury, and premature death.
• Achieve health equity, eliminate disparities, and improve the health of all groups.
• Create social and physical environments that promote good health for all.
• Promote quality of life, healthy development, and healthy behaviors across all life stages

So what cane be derived from these goals is that ideally Healthy 2020 would like to prevent the incidence of down syndrome (which may be impossible), improve the current health of the population of down syndrome people, create an environment where people with down syndrome can thrive, and promote and encourage healthy growth for all ages of people with Down syndrome.

MICH-2

There are many objectives that strive to improve Down syndrome situations indirectly in Healthy People 2020, but the only objective in Healthy people 2020 that is directly related to individuals with Down syndrome is the Maternal, Infant, and Child Health Data Details number 2. This objective reads to reduce the 1-year mortality rate for infants with Down syndrome for every one thousand live births of infants with Down syndrome. This Healthy People 2020 outcome uses the number of live born infants with a confirmed Down Syndrome diagnosis that died in the first year of life as the numerator and uses the number of love born infants with a confirmed diagnosis of Down Syndrome as the denominator. However, this outcome only measures for those with trisomy 21 down syndrome and excludes those diagnosed with mosaic down syndrome, and of these data only 14 states contributed their statistics.

Interventions

Guam CEDDARS

One of the greatest resources to the island of Guam and those affected by Down syndrome is the University of Guam Center for Excellence in Developmental Disabilities Education, Research & Service. Their mission is to create partnerships and pathways to increase the quality of life of individuals with developmental disabilities and their families.

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