In order to study them, we’ll be categorizing the disorders into three groups so that we can list the main ones:
– Birth defects: anatomical disorders that can be explained by embryology;
– Biological disorders: all blood and humoral imbalances of biochemical, cellular, immune or infectious origin,
– Other functional disorders.
MALFORMATIONS
Before birth
Some digestive, diaphragm and abdominal wall disorders can be detected in utero by ultrasound, which usually leads to genetic testing.
After birth
The duodenum is the first segment of the small intestine. It may be subject to complete interruption (atresia), manifesting in newborns with bilous vomiting, or narrowing (stenosis), which can sometimes be late to manifest once solid foods have been introduced. Atresia and duodenal stenosis are observed among 3.9% of babies with Down syndrome. They are more common among boys, and they require surgical treatment. The annular pancreas, where the pancreas encloses the duodenum, is similar.
An artery arising from the aorta – the right subclavian artery – may be abnormally located and compress the esophagus. This is found among 12% of children with Down syndrome suffering from cardiopathy.
Hirschsprung’s disease (2.76%) results from the absence of nerve cells in the wall of the colon, which leads to intestinal obstruction. The longer the segment without nerve cells, the more severe the disease. The surgeon removes the paralyzed segment. Patients are most diagnosed at 48 hours of life. When the paralyzed segment is limited to the anus region, the diagnosis is more difficult.
Imperforation of the anus (or anorectal atresia) is quite common in children with Down syndrome (1.16%). Intervention must be prompt because of the risk of perforation.
Congenital anomalies of the liver vessels have been described.
Cleft lip and palate are slightly more common in children with Down syndrome (0.6%) than in the general population (1/750). Bifid uvula (4.63%) and submucosal cleft palate (0.77%) are weaker, more common forms of these disorders.
Esophageal atresia (interruption of the esophagus) affects 0.5-0.9% of babies with Down syndrome (1/3500 of the general population).
Pyloric stenosis affects 0.3% of babies with Down syndrome (5/1000 of the general population).
Numerous cases of diaphragmatic hernia (a breach in the diaphragm allowing abdominal organs to pass into the thorax) have been published.
Malrotation of the small intestine is also possible.
BIOLOGICAL, IMMUNOLOGICAL AND INFECTIOUS DISORDERS
During birth
Physiological jaundice can occur in all newborns, i.e. benign jaundice related to the breakdown of excess red blood cells following birth. However, pathological jaundice – known as retention jaundice – can also occur in 3.9% of Down syndrome babies, with discolored stools and brown urine, which can be due to several causes.
After birth
Several studies have shown the frequency of low vitamin D levels in people with Down syndrome, including in sunny countries. They should therefore be given vitamin D as a matter of routine.
Helicobacter pylori infection is common. This bacterium causes stomach irritation (gastritis), and may even result in an ulcer of the stomach or duodenum. The bacteria is present in the saliva and stools of infected people, with most common signs being poor weight growth, abdominal pain and anemia. Blood tests are used to screen for the bacteria.
Non-alcoholic cirrhosis associated with fatty liver may occur among children with Down syndrome, and even in non-obese children and adults. It may be brought on by sleep apnea.
Biliary lithiasis and sludge are very common, most often discovered on routine ultrasound. Among children with Down syndrome under 3 years of age, 6.9% had biliary lithiasis and 2.1% had biliary sludge.
The overall prevalence of celiac disease (gluten intolerance) is estimated at 6.6% in children and 5.1% in adults with Down syndrome, which justifies its routine screening by blood examination. More often than not, it isn’t associated with any digestive disorder.
Geographic tongue is encountered in 4% of children with Down syndrome. It is frequent and benign. Doctors need to reassure patients and look for unpleasant sensations that suggest mycotic superinfection.
Several studies have shown the sensitivity of people with Down syndrome to the hepatitis B virus and their predisposition to develop chronic hepatitis. Vaccination is strongly recommended. No increased incidence of hepatitis A has been found.
Several cases of Crohn’s disease have been published, with the main signs being abdominal pain, weight loss and diarrhea.
A few cases of pancreatitis have been published in children with Down syndrome, with intense abdominal pain evoking the diagnosis.
Immune disorders of the liver (autoimmune hepatitis and cholangitis) have been reported, manifesting in fatigue, nausea, weight loss and pruritus.