Genetics for Nurses in Pediatric Disciplines. A guide to recognition and referral of congenital and genetic disorders AUTHORS: Golder N. Wilson MD PhD, 1 Vijay Tonk PhD, 2 REVIEWERS Shirley Karr BSN RN, 3 Joanna K. Spahis BSN CNS, 4 Shirley Myers, 5 RNC, MSN, FNP, and Sherry Letalian RN 6
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A guide to recognition and referral of congenital and genetic disorders
Golder N. Wilson MD PhD,1 Vijay Tonk PhD,2
Shirley Karr BSN RN,3 Joanna K. Spahis BSN CNS,4 Shirley Myers,5 RNC, MSN, FNP, and Sherry Letalian RN6
1Clinical Professor of Pediatrics, Texas Tech University Health Science Center at Lubbock and Private Practitioner, KinderGenome Genetics, Dallas Texas; 2Professor of Pediatrics and Obstetrics-Gynecology; Director, Cytogenetics Laboratory, Texas Tech University Health Science Center at Lubbock;3Genetics Coordinator, Maternal-Fetal Medicine and Genetics, Texas Tech University Health Sciences Center at Amarillo;4Pediatric Clinical Nurse Specialist in Genetics and Coordinator of the Down Syndrome Clinic, Department of Genetics, Children’s Medical Center of Dallas5Women’s Health Nurse Practitioner, Maternal-Fetal Medicine and Genetics, Texas Tech University Health Sciences Center at Amarillo;6Pediatric Clinic Coordinator, Department of Pediatrics, Texas Tech University Health Sciences Center, Lubbock
This presentation was designed as part of the GEN-ARM (Genetics Education Network for Nursing Assessment, Recognition, and Management) for the Mountain States Region Genetics Collaborative (MSRGCC); contact www.mostgene.org or Ms. Joyce Hooker at [email protected]
Genetic diseases affect 5-10% of children
Nurses can recognize and refer genetic disorders without need for esoteric genetic knowledge
We will now present cases where your nursing skills and alertness (REYDAR=Recognize, EYDentify, Assess, Refer) can greatly benefit children with genetic diseases.
These cases will introduce you to simple principles of genetics that will give you confidence in recognizing these patients and foster a medical home
These cases and principles are geared to the nursing genetics primer and resources on the GENARM CD
Newborn with large head and deformed bones with fractures by x-ray
The family history indicated that the mother and other relatives had mild features of osteogenesis imperfecta or brittle bone disease (see Chapter 2)
Suspicion of genetic disease underlying this unusual infant led to referral and genetic counseling for this autosomal dominant disease—mother’s guilt about her accident was assuaged and she learned she had a 50% chance each of her future children would have OI
Categories of genetic disease relate to the steps from gene to family (genetic hierarchy)
Sickle cell anemia is recessive, requiring both distinctive family patternsβ-globin alleles to be abnormal (SS versus AS trait or AA normal).
Sickle cell anemia can be predicted (25% risk for next child) and tested (abnormal S protein or gene)
Other inherited anemias can be related to different abnormal globin alleles (C, D, E, thassemias).
A or S
Know categories, not rare diseases (genotype Oo)
Mendelian diseases reflect transmission of single genes (abnormal alleles) = DNA diagnosis
Multifactorial diseases reflect multiple abnormal genes plus environment = DNA/HLA markers
Many genes altering development cause isolated birth defects like cleft palate
Many genes altering enzyme pathways cause common metabolic diseases
(e.g., adult-onset diabetes, hyperlipidemia)
Many genes altering organ function(s) produce adult diseases (e.g., schizophrenia)
Chromosomal diseases imbalance multiple genes and cause multiple birth defects = Karyotype
REYDAR of common pediatric presentations (genotype Oo)
Recognition → Category → Referral ↔ Medical home
(see Chapter 1)
Case 1N. Newborn with feeding problems (genotype Oo)(see Chapter 1 of primer)A term female infant exhibited slow growth in the last trimester of pregnancy but had normal ultrasound studies. After normal delivery and borderline low birth weight (5 lbs), the mother reported difficulty breast-feeding. Lactation education and reassurance were given and the infant was discharged with mild jaundice and a weight loss of 5% from her birth weight. Was this management appropriate?What additional history might have been helpful?
REYDAR of common pediatric presentations
Recognition to category to referral and management
Case 1N (cont): Important history was that this child was mother’s second--her child was the problem, not her breast-feeding. The child’s low muscle tone and subtle facial changes (down-slanting palpebral fissures, broad nasal bridge, down-turned corners of the mouth) led to evaluation after discharge with chromosome studies that showed deletion of the number 4 short arm (4P- or Wolf-Hirschhorn syndrome. Recognition of H&P signals was the key to REYDAR, not knowledge of a rare disease.
Routine chromosome analysis (karyotype) will show the extra chromosome 21 that is characteristic of Down syndrome which normally requires at least 5-7 days for results.
13 chromosome 21 that is characteristic of Down syndrome which normally requires at least 5-7 days for results.
Cloned DNA segment
from target chromosome
13, X, Y
No culture or need for
Now a rapid FISH test is available that does not require stimulation of white blood cell division and gives results within 2-4 hours. Rapid FISH highlights chromosomes commonly involved in disorders—e.g., 13 (Patau syndrome), 18 (Edwards syndrome), or 21 (Down syndrome), showing three versus the normal two FISH signals in each cell nucleus (X and Y probes also show Turner syndrome or document sex in cases of ambiguous genitalia)
A 6-year-old girl is having trouble keeping up in the first grade because of distractibility and poor comprehension. She had some problems breast-feeding and later needed speech therapy. Her school nurse noted a somewhat unusual facial appearance with narrow eyes, long face, and prominent nose; she also had long fingers and a faint heart murmur. The child’s teacher felt she was a discipline problem due to attention deficit or conduct disorder and suggested possible medication therapy. Do you agree?
The subtle facial changes, speech delay, and school problems suggest mild mental disability--such children may be labeled as unmotivated or hyperactive unless the underlying congenital problem is recognized. This child had the Shprintzen-DiGeorge spectrum (OMIM #192430), proven by FISH testing showing submicroscopic chromosome 22 deletion (her parents were normal). Referral to cardiology showed a small cardiac defect and arrythmia; medication was needed, but not for the learning problem.
See Chapter 7 for more information
A pediatric nurse conducts a school physical on a 6-year-old boy who is very tall for his age. He has a height beyond the 97th centile despite average weight and head circumference, and his parents are not tall. The nurse notes other findings including an aged facial appearance, lax joints, heart murmur, and concave chest. The nurse suspects a genetic condition, and documents a family history
The family history shows numerous relatives with heart problems on the father’s side. The father (individual III-2) is not unusually tall (5’ 10”) and has no eye or heart problems. However, the father’s brother (individual III-1) developed aortic dilation and insufficiency at age 39, was 6’ 5” tall, and had a lean build with flat feet and inguinal hernias.
Disorders with extreme tall stature (gigantism), short stature (dwarfism), or failure to thrive are often genetic
The fetal growth changes would be consistent with fetal alcohol syndrome but the severe microcephaly suggested anencephaly (OMIM #206500, others). Of growing importance in pediatrics is preconception care, illustrated here by the fact that folic acid taken early in pregnancy lowers the incidence of neural tube defects like anencephaly or spina bifida by 2/3. As with maternal diabetes, prevention must begin before planning the pregnancy since a missed period may not be noticed until 3-4 weeks after conception (after the primitive streak stage)
Table 4.1. Multifactorial Disorders in the United States
*Ranks first for neonatal causes of death; approximate scale: ++++ (100% of predisposition due
to genetic factors as for Mendelian disorders) to + (20% of predisposition due to genetic factors)
Multifactorial Disorders important priorities because recognition of pregnancy by a missed period (3-4 weeks embryonic age) may be too late for preventive measures
Multifactorial disorders: For some (e.g., coronary artery disease), single genes of major effect (e.g., those regulating cholesterol) are good risk markers)
Recognizing at-risk children or adolescent females provides important opportunities for nursing education and prevention (see chapter 4)
6. and exaggerated jaundice with a total bilirubin of 14 at day 2 of life. Your assessment reveals the infant is less responsive than early on your shift, and you note decreased muscle tone with a poor suck. The prenatal history is normal except that the mother and father are from Pakistan and are second cousins. Which of the following conditions would be most likely in this infant? Which of the following birth defects would be most likely to occur in this situation?