About trisomy 9 (complete trisomy 9 syndrome), included

What is trisomy 9 (complete trisomy 9 syndrome), included?

General Discussion

Chromosome 9, Trisomy Mosaic, also known as Trisomy 9 Mosaicism syndrome, is a rare chromosomal disorder in which the entire 9th chromosome appears three times (trisomy) rather than twice in some cells of the body. The term "mosaic" indicates that some cells contain the extra chromosome 9, while others have the normal chromosomal pair.

What are the symptoms for trisomy 9 (complete trisomy 9 syndrome), included?

The specific symptoms of trisomy 9p can vary greatly from one person to another due, in part, to the specific length of the duplicated material on chromosome 9p.

Trisomy 9p is often characterized by low muscle tone (hypotonia) as well as growth deficiency and delayed bone maturation, which means that the rate of growth and development of the Bones is slower than in individuals with 46 chromosomes. Hypotonia can affect infants, most often related to Difficulty feeding, resulting in the failure to gain weight and grow at the expected rate (Failure to thrive). In general, growth deficiency primarily begins after birth (postnatally). Some infants may also experience oropharyngeal dysphagia, in which there is difficulty emptying food or drink from the back of the throat at the back of the mouth (oropharynx) into the esophagus. However, reports indicate that, in those with larger trisomic segments (e.g., through bands 9q22 or 9q32), growth deficiency may begin before birth (intrauterine growth retardation). Microcephaly, a condition indicates that the head circumference is smaller than would be expected based upon an infant’s age and gender, is also apparent in infancy.

In many cases, trisomy 9p is also associated with varying degrees of intellectual disability, ranging from moderate to severe, and delays in the acquisition of skills requiring the coordination of mental and physical activities (developmental coordination disorder). According to reports in the medical literature, language development appears to be most severely delayed. Learning disabilities, ranging from mild to severe, also occur. Intellectual and learning issues go hand in hand. Intellectual and learning disabilities represent a broad range, especially when the children with partial trisomy 9p are considered as well. The gap with typically developing peers will often widen with age.

Many infants and children with trisomy 9p also have a characteristic facial appearance. Most individuals with this condition present with a short and broad head (brachycephaly); a wide mouth with downturned corners; a prominent, relatively bulbous nose; large, low-set, “cup-shaped” ears; and/or a short vertical groove in the center of the upper lip (philtrum). Characteristic eye abnormalities may also be present, such as deeply set, widely spaced eyes; downwardly slanting eyelid folds (palpebral fissures); vertical skin folds that may cover the eyes’ inner corners (epicanthal folds); and/or abnormal deviation of one eye in relation to the other (strabismus). Some affected infants may also have a short, webbed neck; a highly arched roof of the mouth (palate); and/or widely spaced nipples. Teeth may erupt later than expected and may emerge crooked. In addition, in those with larger trisomic segments, additional craniofacial features may include a small jaw (micrognathia), incomplete closure (clefting) of the roof of the mouth (cleft palate), and/or an abnormal groove or gap in the upper lip (cleft lip).

Many individuals with trisomy 9p may also have various anomalies of the hands and feet. These may include decreased length of specific Bones of the fingers and toes (phalanges) and within the hands (metacarpals) and feet (metatarsals); short fingers and toes (digits) with small nails; and/or the pinkies may be fixed or ‘locked’ in a bent position (clinodactyly). The syndrome may also be associated with unusual, distinctive skin ridge patterns of the fingers and hands (abnormal dermatoglyphics), including a single flexion crease on the fifth fingers and a reduced total finger ridge count. Less often, a single crease across the palms may also be present.

In some cases, trisomy 9p may be associated with skeletal defects including delayed closure of the “soft spots” (fontanels) and the fibrous joints (cranial sutures) between certain? Bones of the skull; a deformity in which the foot is twisted out of shape or position (clubfoot); and/or abnormal front-to-back or side-to-side curvature of the spine (kyphoscoliosis) that may develop during the second decade of life. Less commonly, partial webbing (syndactyly) of certain fingers and toes and dislocation of the hips at birth have been noted.

Approximately five to 25% of children with may also have congenital heart defects, particularly an abnormal opening in the partition (septum) that separates the two lower chambers (ventricles) of the heart (ventricular septal defects [VSDs]). In those with cardiac defects, associated symptoms and findings may vary, depending upon the size, nature, and/or combination of heart malformations present. For example, in some cases, such as those with small, isolated VSDs, no symptoms may be apparent (asymptomatic). However, in other instances, such as children with larger VSDs and/or other cardiac defects, associated symptoms and findings may include difficulties feeding, Shortness of breath, profuse Sweating, Irritability, Fatigue, bluish discoloration of the skin and/or mucous membranes (cyanosis. In severe cases, congenital heart disease may lead to potentially life-threatening complications. Surgery may be necessary to remedy heart defects along with follow-up care and monitoring.

In some instances, additional physical abnormalities have been reported. These have included genital malformations in affected males, such as undescended testes (cryptorchidism) and/or abnormal placement of the urinary opening (hypospadias); kidney (renal) malformations; protrusion of part of the intestine and the fold of fatty membrane in front of the intestine (omentum) through a defect in the abdominal wall at the navel (umbilical hernia); and/or hydrocephalus, in which blockage of the normal flow of spinal fluid leads to excessive amounts of cerebrospinal (CSF) fluid accumulating in and around the brain. This leads to abnormally high pressure within the skull and Swelling of the head, and can result in neurological impairment. CSF is the watery protective fluid that circulates through the cavities (ventricles) of the brain, the canal containing the spinal cord (spinal canal), and the space between layers of the protective membranes (meninges) surrounding the brain and spinal cord (i.e., subarachnoid space). Depending upon the age at symptom onset and other factors, associated symptoms may include sudden episodes of uncontrolled electrical activity in the brain (Seizures), Irritability, Vomiting, Headache, loss of coordination, deteriorating mental functioning, and/or other findings.

Some individuals may also develop a brain malformation known as Dandy-Walker malformation (DWM). DWM occurs during embryonic development of the cerebellum and 4th ventricle. The cerebellum is an area at the back of the brain that helps coordinate movement, and, to a lesser extent, may be involved with some cognitive and behavioral functions. The 4th ventricle is a space around the cerebellum that channels fluid from inside to around the outside of the brain. DWM is characterized by improper development (e.g. small size and abnormal position) of the middle part of the cerebellum known as the cerebellar vermis, cystic enlargement of the 4th ventricle and enlargement of the base of the skull (posterior fossa). DWM may be associated with hydrocephalus. 

Affected children may be below average height for their age (short stature). In some cases, affected children have been diagnosed with growth hormone deficiency.

What are the causes for trisomy 9 (complete trisomy 9 syndrome), included?

In many cases, the trisomy appears to result from spontaneous (de novo) errors very early in embryonic development that occur for unknown reasons (sporadically). In such de novo cases, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality.

In approximately 50% of cases, trisomy 9p may be due to a balanced chromosomal rearrangement in one of the parents. In most cases, the parental rearrangement is described as a “balanced translocation.” Translocations occur when portions of a chromosome break off and are rearranged, resulting in shifting of genetic material and an altered set of chromosomes. However, no genetic material is gained or lost, only rearranged. If a chromosomal rearrangement is balanced, meaning that it consists of an altered but balanced set of chromosomes, it is usually harmless to the carrier. However, such a chromosomal rearrangement may be associated with an increased risk of abnormal chromosomal development in the carrier’s offspring. Such children may inherit an unaltered set of chromosomes, the same balanced translocation as the parent, or an unbalanced translocation, in which a chromosome has extra (trisomic) or missing (monosomic) genetic material.

Rare cases have also been reported in which the parental chromosomal rearrangement has been an inversion. An inversion is characterized by breakage of a chromosome in two places and reunion of the segment in reverse order from the original arrangement.

Chromosomal analysis and genetic counseling are typically recommended for parents of an affected child to help confirm or exclude the presence of a balanced translocation or other chromosomal rearrangement involving chromosome 9 in one of the parents.

Specific Breakpoints and a “Critical Region” In individuals with trisomy 9p, all or a portion of the short arm (p) of chromosome 9 (9p) appears three times (trisomy) rather than twice in the cells of the body. In addition, in some cases, a portion of the long arm of chromosome 9 (9q) may also be trisomic (duplicated). In extremely rare cases, individuals with a trisomic portion of 9p may also have a deleted or missing (monosomic) portion.

Evidence indicates that, in many cases, clinical features may be relatively similar among affected individuals despite differing lengths of the duplicated segment of 9p. According to some researchers, such findings suggest that certain characteristic abnormalities associated with the syndrome may result from trisomy of the end (distal) portion of 9p. (“Distal” indicates away or farthest from a particular point of reference, meaning the chromosome’s centromere. The distal region of 9p is sometimes referred to as “9p2” and includes bands 9p21 through 9p24, the latter of which is the end or “terminal” band of 9p [also known as “9pter”].) However, in individuals with larger trisomies, such as those that extend through bands 9p22, additional clinical findings may also be present that appear to correlate with the extent of the duplication.

Generally, according to investigators, trisomies involving part or all of 9p and, in some cases, extending to 9q11-13 may be characterized by intellectual disability and distinctive craniofacial malformations already described. However, in addition to such features, intrauterine growth retardation, congenital heart defects, other skeletal abnormalities (e.g., congenital hip dislocation), and additional craniofacial malformations (e.g., micrognathia, cleft lip and cleft palate) are more common with trisomies extending to or including band 9p21.3-p24. Researchers believe that 9p22 is a “critical” region responsible for most of the classic symptoms of trisomy 9p. However, there are individuals reported in the medical literature who have duplications involving this region and exhibit only mild symptoms. More research is necessary to determine the specific correlation between the duplicated segment of 9p and the associated symptoms and whether additional factors such as modifier genes play a role in the development of specific symptoms in each individual case. twice in the cells of the body. In addition, in some cases, a portion of the long arm of chromosome 9 (9q) may also be trisomic (duplicated). In extremely rare cases, individuals with a trisomic portion of 9p may also have a deleted or missing (monosomic) portion.

What are the treatments for trisomy 9 (complete trisomy 9 syndrome), included?

Treatment The treatment of trisomy 9p is directed toward the specific symptoms and physical findings that are displayed in each individual. Such treatment may require the coordinated efforts of a team of medical professionals, such as pediatricians; surgeons; physicians who diagnose and treat abnormalities of the skeleton, joints, muscles, and related tissues (orthopedists); physicians who specialize in heart abnormalities (cardiologists); neurologists; and/or other healthcare professionals. Genetic counseling is recommended for families with children affected by this condition. Psychosocial support for the entire family may be needed as well.

Early intervention services during infancy and toddlerhood (before the age of three) are important in ensuring that affected children reach their potential. Early speech therapy for children who experience severe communication and language problems is extremely important. Special services that may be beneficial during childhood include special education, physical therapy, occupational therapy, speech therapy and/or other medical, and social services. In the US, an Individualized Family Support Plan (IFSP) may be developed to guide the early intervention process for infants and toddlers with disabilities. An Individualized Education Program (IEP) may be developed to assist children in school if special services are required, or a Section 504 plan which can ensure that the child receives access to an equal education through accommodations in their learning environment. Vocational and habilitation services are often necessary during adulthood.

Additional treatment for this disorder is symptomatic. For example, for congenital heart defects, treatment with medication, surgical intervention (palliative and/or corrective), and/or other measures may be required. In addition, in some cases, physicians may recommend surgical repair or correction of characteristic craniofacial malformations, skeletal abnormalities, genital defects, hernias, renal anomalies, and/or other malformations associated with the disorder. The specific surgical procedures performed will depend upon the nature and severity of the anatomical abnormalities, their associated symptoms, and other factors. In addition, growth hormone deficiency has been successfully treated with supplemental growth hormone.

What are the risk factors for trisomy 9 (complete trisomy 9 syndrome), included?

Trisomy 9 (complete trisomy 9 syndrome) is a rare chromosomal syndrome characterized by an extra chromosome 9. It arises from random errors that occur very early in embryonic development for unknown reasons.

Risk factors

  • Age: Maternal age is the most critical risk factor for trisomy conditions. Women in their late 30s and 40s have a higher chance of getting affected by trisomy 9 (complete trisomy 9 syndrome).
  • Miscarriage: Most miscarriages in the first trimester are associated with chromosome anomalies, and trisomy 9
  • Cardiac defects: Trisomy 9 (complete trisomy 9 syndrome) leads to Congenital heart defects.
  • Skeletal abnormalities: The most common risks include dislocated large joints, especially hips and knees, and hand anomalies.
  • Central nervous system anomalies: Brain malformations and neurodevelopment delay are significant risks in infants affected by the syndrome.
  • Multiple malformations: The syndrome includes severe retardation of the growth.
  • Others: growth restriction is almost an invariable feature.

Most cases of Trisomy 9 (complete trisomy 9 syndrome)are not inherited and often occur sporadically during the formation of the reproductive cells. The signs and symptoms may include intellectual disability, delays in d development, and growth problems. A doctor may use regular checkups to determine the diagnosis.

Vision problems,Dislocated joints,Kidney cysts,Vision problems,Feeding and breathing difficulties

Cognitive disabilities,Congenital heart defects,Developmental delay,Displaced joints,Failure to grow well

Prenatal vitamin that contains 400 micrograms of folic acid

Is there a cure/medications for trisomy 9 (complete trisomy 9 syndrome), included?

Trisomy 9 (also called complete trisomy 9 syndrome) is a genetic disorder that causes serious health problems and developmental delays. It's caused by having three copies of chromosome 9 instead of the usual two. This means that all body cells will have three copies of each gene on chromosome 9.

  • The current treatment for trisomy 9 is supportive care—this means providing the best possible environment for your child to grow up in, as well as medication and therapies to help with symptoms like seizures or behavioral issues. But there are no cures for this disorder at this time.
  • There's no cure for trisomy 9, but there are medications and therapies that can help manage the symptoms.
  • There are a few medications that are used to treat epilepsy in children with trisomy 9, including lamotrigine (Lamictal) and topiramate (Topamax). The doctor might also prescribe a benzodiazepine, such as clonazepam (Klonopin), to help with anxiety and sleep problems.
  • The doctor may also recommend behavioral therapy for your child's developmental delays and communication problems. This could include speech therapy, occupational therapy, or physical therapy.
  • If your child has any serious symptoms of trisomy 9 syndrome—such as seizures or severe developmental delays—you should talk to your doctor about getting an MRI scan of their brain to check for any signs of brain damage caused by the condition.
Vision problems,Dislocated joints,Kidney cysts,Vision problems,Feeding and breathing difficulties

Cognitive disabilities,Congenital heart defects,Developmental delay,Displaced joints,Failure to grow well

Prenatal vitamin that contains 400 micrograms of folic acid

Video related to trisomy 9 (complete trisomy 9 syndrome), included