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Clinical and Metabolic Genetics
Clinical and Metabolic Genetics

22q Fact Sheets

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What is 22q11 DS?
Communication Issues and 22q11 DS
Calcium Regulation and 22q11 DS
Genetics Glossary
The 10 Warning Signs of Primary Immune Deficiency
22q DS and the Immune System

 

 

What is 22q1 DS?

22q Deletion Syndrome (22q DS), which is also known as DiGeorge syndrome and Velo-Cardio-Facial syndrome, can affect many different parts of the body. People with 22q Deletion Syndrome have a small piece of chromosome 22 missing, which is called a microdeletion. This microdeletion involves many genes

What are some of the common medical issues associated with 22q DS?

Calcium: Children with 22q Deletion Syndrome may have decreased calcium levels. Maintaining a good dietary source of calcium is very important, as extremely low calcium levels can lead to seizures (convulsions). Lifelong monitoring of calcium is important, as calcium levels can drop during illness, with the stress of surgery, and during adolescence (puberty), and pregnancy.

Kidneys: Children with 22q Deletion Syndrome can have kidney abnormalities, such as underdeveloped, cystic kidneys, or even a missing kidney. Every child with a new diagnosis of 22q Deletion Syndrome should have a kidney ultrasound, if not already done.

Immune System: Children with 22q Deletion Syndrome can have partial immunodeficiency. This means that their immune system is not as strong as it should be and not as effective at fighting infections. If your child has partial immunodeficiency, you may receive special counselling about immunizations for your child.

Thyroid: Children with 22q Deletion Syndrome can have problems with their thyroid function (both underactivity and overactivity of the thyroid has been reported). Regular thyroid testing can help to detect and effectively treat any problems that may be identified.

Heart: Congenital heart defects are more common in children with 22q Deletion syndrome. These can range from a simple "hole in the heart" to a complex defect that may require multiple surgeries. All children with 22q Deletion Syndrome should have a cardiac assessment, even if there are no signs of a heart defect.

Platelets: Children with 22q Deletion Syndrome may have low platelet counts (platelets are a component of blood which function in clotting). Platelet counts should be checked once a year and prior to any surgeries your child may have.

Velopharyngeal Insufficiency (VPI) VPI is a common feature of 22q Deletion Syndrome. It involves failure of the palate to meet the throat during crying, swallowing and speech. This often results in nasal-sounding speech and nasal regurgitation, in which fluid comes through the nose during feeding. Removing the adenoids can lead to the development of VPI in some children. Therefore careful consideration should be given to the benefits and risks of this type of surgery.

What are some of the developmental issues associated with 22q DS?

Speech and Language: Many individuals with 22q Deletion Syndrome experience difficulties with speech and language development. A speech pathologist with specific expertise in the evaluation of children with 22q Deletion Syndrome can look for signs of any of the speech difficulties commonly observed in children with 22q Deletion Syndrome.

Learning and Schooling: Many children with 22q Deletion Syndrome have some degree of learning difficulties, specifically in the areas of language and math. The developmental progress of your child can be monitored, and if concerns arise, they can be identified early. If concerns arise, your child may benefit from a developmental or psycho-educational assessment.

Mood and Behaviour: Behavioural and psychiatric disorders are more common in individuals with 22q Deletion Syndrome. We know that there are benefits to the early recognition and intervention for these conditions. If any concerns should develop regarding your child's mood or behaviour, a formal psychological or psychiatric assessment may be helpful.

Why do we call 22q DS a genetic syndrome?

We know from past experience that in the majority of cases, microdeletion of chromosome 22 is not inherited, rather it occurs for the first time in the affected child. In a small number of cases, however, the disorder is inherited from a parent. Genetic testing is available to parents of all newly diagnosed children. Your child will have a 50 per cent chance of passing 22q Deletion Syndrome on to future children. At this time it is not possible to predict what medical or developmental concerns would be present in any child who might inherit 22q11-deletion syndrome. However, there are currently several research studies underway to try to learn more about the variable medical and other concerns associated with this condition.

It is important to remember that each child with 22q Deletion Syndrome is different. Some children will have many of the health concerns listed above, while others will have very few. Working together with your child's doctors teachers and other care-providers will help them understand your child's unique needs.

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Communication Issues and 22q11 DS

22q DS: A Guide for Speech and Language Pathologists
by Paula Klaiman, Speech and Language Pathologist

22q Deletion Syndrome is a genetic condition with an incidence of approximately 1 in 4,000. The range of clinical findings is extensive and variable, and affects nearly every organ and system of the body. The most common features include: congenital cardiac anomalies, palatal defects including hypernasal speech, immune deficiencies, hypocalcemia, developmental delay, learning disorders, dysphagia and mild facial dysmorphism. For a more detailed clinical description you may wish access information on the internet at the following Web site: www.vcfsef@hscyr.edu

As the medical community becomes more aware of this syndrome, many are referring for screening for 22q deletion at earlier ages. This is particularly true for children presenting with cardiac anomalies at birth. This early diagnosis allows for the screening of known potential deficits and allows the initiation of early intervention. This is particularly important to Speech Language Pathologists involved in the treatment of young children. Because the effect of the deletion on early development is so widespread and devastating to early communication and behaviour, every child with the deletion should be considered at risk for communication disorders and should therefore be enrolled in an early intervention program as soon as the diagnosis is made. A proactive stance is recommended in the management of these patients (Solot et. al. 2001). Children with 22q deletion syndrome are universally delayed in their acquisition of language milestones and once expressive language and speech skills begin to emerge, they are disproportionately low in comparison to their receptive language delay. Furthermore, the speech, language and learning patterns in these children may be unique and may require more specialized intervention strategies (Golding-Kushner, 2001). Therefore, knowledge of the pattern of communication impairment may lead to more effective and efficient intervention procedures.

Speech and Language Impairment in 22q Deletion Syndrome

  • VPI: May be related to cleft palate, submucous cleft palate (overt or occult), hypotonia, palatopharyngeal disproportion or post-adenoidectomy. Characteristics associated with VPI include: hypernasality, audible nasal air emission on high pressure consonants, nasal/facial grimacing, compensatory articulation substitutions (particularly glottal stops), nasal substitutions, omitted consonants, or weak pressure on oral consonants.
  • Respiratory and phonatory disorders: strained-strangled voice, decreased loudness, high-pitched voice, poor respiratory support (vocal fatigue at the end of a phrase, reduced syllables per breath).
  • Low muscle tone: flat facies, open mouth at rest, drooling, tongue protrusion, palatal hypotonia (VPI), nasal regurgitation, feeding disorders.
  • Delayed acquisition of language milestones:This delay is universal and is often greater than the delay in general cognitive development.
  • Motor speech disorders: poor imitation, groping oral movements, poor stimulability, poor sequencing of sounds.
  • Articulation or phonological error patterns: high incidence.

Guidelines for intervention in 22q Deletion Syndrome infants and preschool children.

  • Parent Training and Caregiver Consultation
  • Suggestions specific to 22q Deletion Syndrome:
  • Prevent the establishment of compensatory articulation substitutions, particularly glottal stops. Train parents and caregivers to recognize the difference between oral and compensatory articulation. Behaviour modification techniques can then be applied with parents ignoring compensatory productions (negative reinforcement) and positively reinforcing oral productions. The difficulty with this approach is trying still to reward the child’s communication attempts. If the child is producing a word with glottal stops, encourage the parent to model the correct response exaggerating the aspects of the child’s production that needs to be corrected. Parents may want to replace the utterance with an easier target word.
  • Encourage oral airflow for non-speech activities as a visual aid. This will lay the foundation for increasing oral airflow and pressure during the production of early developing phonemes.
  • Enhance expressive vocabulary by targeting words containing phonemes already in the child’s repertoire or sounds that are easier to produce (vocalic and nasal consonants). Do not target words that begin with vowels since vowel-initial words begin with a glottal stop.
  • Target aspirated and sustained productions of "hhhhh" and then begin to overlay mouth opening and closing in order to approximate /p/.
  • Focus on the correct articulatory placement of early developing sounds and do not worry about hypernasality. You can train parents to gently occlude their child’s nostrils in order for the child to hear the correct target.
  • For non-verbal children, alternative communication strategies may help to reduce frustration, increase communicative competencies, stimulate imitation skills and bridge the gap towards the development of more conventional speech/language symbols.

General learning/behavioural characteristics to keep in mind when planning intervention

  • Difficulty retaining information from a single presentation. Sessions should be frequent and short. If this is not possible, take frequent breaks (every 10-15 minutes).
  • There are a wide variety of behavioural characteristics associated with this population which may influence the way therapy is structured. Some children may be very shy and inhibited, phobic, startle easily or have tactile defensiveness. The clinician may need to "easy into" the child’s space and integrate the parent into activities in order for the child to feel comfortable. Other behavioural characteristics described in this population include: impulsivity, hyperactivity, disinhibition, self-directed behaviour, noncompliance, attention disorders and poor social skills. Some have suggested that these children prefer independent play and do not comply in order to please an audience or receive praise. This may require creative planning in order to engage and motivate a child.

When to Refer for Instrumental Investigation of Velopharyngeal Functioning

All infants diagnosed with 22q Deletion Syndrome will be referred to their community Infant Development Program and Preschool Speech and Language Program. Any preschool child recently identified will also be routinely referred to their community- based Preschool Speech and Language Program. By three years of age, any child presenting with speech characteristics suggestive of velopharyngeal inadequacy (hypernasality, limited oral consonant development, weak pressure consonants, glottal stop or compensatory articulation substitutions), should be referred to The Hospital for Sick Children for further investigation of velopharyngeal functioning. All referrals should be directed to Paula Klaiman, Department of Communication Disorders: Fax (416) 813-6487. All accepted referrals will be sent a parent questionnaire and upon return of the questionnaire, an assessment will be scheduled. The initial assessment will document perceptual judgements of resonance and nasalance values and a decision on whether to proceed with direct visualization of velopharyngeal functioning, via nasopharyngoscopy or multiview videofluoroscopy will be made. Direct visualization may need to be scheduled during a separate appointment depending on clinic availability. For a more detailed description of these procedures, you may visit the SickKids Web site at www.sickkids.ca/plasticsurgery Cleft Palate or Craniofacial Program links.

Children presenting with VPI requiring surgical or prosthetic management will be registered with the Cleft Palate Program and follow up will be determined on an individual basis. For further information regarding referrals, please contact Paula Klaiman at (416) 813-6104 or paula.klaiman@sickkids.ca.

22q Deletion Syndrome Multidisciplinary Clinic at The Hospital for Sick Children

The Hospital for Sick Children has recently established a clinic to provide comprehensive clinical and support services from prenatal to adulthood for individuals with 22qDS. The clinic is also committed to the education of lay and professional people and will conduct research into the areas of medical diagnosis and management. For further information regarding the clinic, contact Andrea Shugar at (416) 813-8365.

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Calcium Regulation and 22q11 DS

What are the calcium problems seen in children with the 22q11.2 deletion?
Stuart A. Weinzimer, M.D., Paediatric Endocrinologist at CHOP, responds:

Children with the 22q11.2 deletion often have hypoparathyroidism, an underdevelopment of the glands that make parathyroid hormone (PTH). PTH is very important for the maintenance of normal calcium levels in the body. Without PTH, the calcium levels may drop to dangerously low levels. Calcium is very important for the body as well. Calcium controls the contractions of muscles, the firing of the nerves, and many other vital functions. Low calcium levels (hypocalcemia) may cause tremors, muscle spasms (tetany), seizures, vomiting, and abnormal rhythms of the heart.

Hypoparathyroidism is usually discovered in the children with a 22q11.2 deletion at birth or shortly thereafter. Sometimes, the finding of a low calcium level is what causes the doctors to order the test to diagnose the 22q11.2 deletion. The hypoparathyroidism that occurs in the newborn period may only be temporary, but there are reports of recurrences of hypoparathyroidism later in childhood. Most likely, these children had mild hypoparathyroidism that persisted and went undetected, but an intervening illness tipped them over the edge. Children with the 22q11.2 deletion who have normal calcium levels at birth do not generally go on to develop hypoparathyroidism later

Hypoparathyroidism is diagnosed by a blood test. The best way to diagnose this problem is to find a low PTH level at the time when the calcium level is low. You may hear about different tests for calcium: total and ionized. Most of the calcium in the bloodstream is attached to proteins. Total calcium measures just that: all of the calcium in the blood, the part attached to proteins and the part that travels freely. Ionized calcium is a measure of just that free portion not attached to proteins. The ionized calcium is a more accurate measure of what is going on in the body, but except for very sick children and in some special situations, the total calcium is a very good measure as well.

If your child is diagnosed with hypoparathyroidism, he or she will need to take special medications to help keep the calcium levels in the body at a safe level. PTH is not given to children, but the calcium levels can be kept normal with a special kind of Vitamin D (not the kind found in milk and in the health food stores). He or she will need to periodically see a paediatric endocrinologist and have the calcium levels checked with a blood test.

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Genetics Glossary

amniocentesis - a procedure in which a small amount of amniotic fluid is removed from the mother's womb in order to detect abnormalities of the fetus

atria - the two upper chambers of the heart

atrial septal defect (ASD) - a hole or defect in the wall between the two upper chambers of the heart

autosomal dominant - a term describing a gene on any chromosome other than the sex chromosomes that produces its effect whenever it is present; can also describe the effect of the gene itself

autosomal recessive - a term used to describe a gene on any chromosome other than the sex chromosomes that produces its effect only when two copies of it are present; can also describe the effect of the gene itself

autosome - one of the 22 pairs of chromosomes other than the sex chromosomes

B cells - cells in the body which make antibodies; their job is to kill germs such as viruses, fungi, and bacteria

birth defect - a health problem present at birth

calcium - a plentiful mineral in the body and the basic component of teeth and bones; essential for cell function, muscle contraction, transmission of nerve impulses, and blood clotting

carrier testing - testing performed to determine whether a person carries one of an altered gene for a particular disease

chromosome - a structure in the nucleus of cells which contains genes

cleft - opening

cleft lip - failure of the lip to close during development; open lip

cleft palate - opening of the roof of the mouth

congenital - present at birth

congenital anomaly - a health problem present at birth

de novo - new, not present previously

deletion - when part of a chromosome is missing, or part of the DNA code is missing

DNA - deoxyribosenucleic acid, the chemical that makes up our genes

dysphagia - feeding difficulties

echocardiogram - an ultrasound of the heart

fluorescence in situ hybridization (FISH) - a laboratory test used to identify extra or missing pieces of chromosomes

gene - a segment of DNA that produces a protein product

genetic - determined by genes or chromosomes

genetic counselling - providing an assessment of heritable risk factors and information to patients and their relatives concerning the consequences of a disorder, the probability of developing or transmitting it, and ways in which it can be prevented, treated or managed.

genotype - the genetic makeup of an individual; what genes are actually present in a person

hypoparathyroidism - under-activity of the parathyroid glands, causing low blood calcium (hypocalcemia)

hypothyroidism - under-activity of the thyroid gland, causing tiredness, cramps, a slowed heart rate, and possibly weight gain

hypocalcemia - low blood calcium levels that may cause tremors, muscle spasms (tetany), seizures, vomiting, and abnormal rhythms of the heart

hypoplastic kidney - a small and underdeveloped kidney

karyotype - a picture of the 46 chromosomes, lined up into 23 pairs

microdeletion - the loss of a tiny piece of a chromosome so small that it is not detectable by a regular microscope

nasal regurgitation - fluid coming through the nose

p arm - the short arm of the chromosome

pedigree - a diagram of a family tree indicating the family members and their relationship to the person with an inherited disorder

phenotype - the visible expression of a gene

platelet - blood cell which assists in blood clotting; throbocyte

posterior pharyngeal flap (PPF) - a surgical procedure to correct velopharyngeal insufficiency (VPI)

q arm - the long arm of the chromosome

renal - related to the kidneys

scoliosis - curvature of the spine

seizure - a sudden loss of consciousness resulting from abnormal electrical activity in the brain

sex chromosomes - the X and Y chromosomes that determine a person's gender; women normally have two X chromosomes and men normally have one X and one Y

syndrome - a collection of traits, health problems, and /or birth defects in an individual which usually has an underlying cause

T cells - cells in the body which are protectors against infection; they include killer, helper and suppressor cells

thrombocytopenia - persistent low blood platelets

thymus - a gland in the chest which is involved in immune function

thyroid - a gland located in the front of the neck below the voice box that plays an important role in metabolism (the chemical processes in the body) and growth; the gland produces thyroid hormone

ultrasound - the use of sound waves to produce an image of an organ inside of the body

velum - soft palate - rear portion of the “roof of the mouth”

ventricles - the lower 2 chambers of the heart

ventricular septal defect (VSD) - a hole in the wall separating the two lower chambers of the heart

velopharyngeal insufficiency (VPI) - failure of the palate to meet the throat (pharynx) during crying, swallowing and speech; often results in hypernasal speech and nasal regurgitation

Adapted from the following sources:

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The 10 Warning Signs of Primary Immune Deficiency

Talk to your doctor about the possibility of primary immunodeficiency disease if your child has more than one of the following:

  • Eight or more ear infections within one year
  • Two or more serious sinus infections within one year
  • Two or more months on antibiotics with little or no affect                                      
  • Two or more pneumonias within one year                        
  • Failure of an infant to gain weight or grow normally
  • Recurrent, deep skin or organ abscesses
  • Persistent thrush in mouth or elsewhere on skin, after age one
  • Need for intravenous antibiotics to clear infections
  • Two or more deep seated infections
  • A family history of primary immune deficiency

Content from the following sources:
http://www.stopgettingsick.com/templates/news_template.cfm/1685

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22q DS and the Immune System

Children born with the 22q Deletion syndrome (also known as DiGeorge syndrome or velocardiofacial syndrome), may have a weaker immune system compared to other children.  This means that they may have more difficulty “fighting off” infections.  Fortunately, the majority of children with 22q DS will not develop any serious immune problems.  Until your child has had a proper immunology assessment, you should take the following precautions:

  • Your child should not receive any live viral vaccines, such as measles, mumps, rubella, oral polio or chicken pox vaccine.
  • If your child needs to receive a blood product (a blood transfusion), it must be negative for the cytomegalovirus (CMV) and irradiated.  Have your doctor check with an immunologist prior to any blood product administration.
  • If your child is exposed to chicken pox, he/she may need to receive Zoster Immune Globulin, an injection of antibodies against chicken pox that modifies the course or may protect children for 30 days from developing the disease. Children need to receive the injection at every exposure that occurs more than 30 days since the last injection.
  • If your child develops chicken pox, your doctor should consult with an immunologist, as your child may need an antiviral medication. 

These precautions should be followed until your child has had an immunology assessment.  At that point, your immunologist will make recommendations that are specific to your child’s situation.