Handbook of Genetic Counseling/Cleft Lip - Isolated, Unilateral, Incomplete

Cleft Lip - Isolated, Unilateral, Incomplete

Contracting

Acknowledge previous contact
What were you hoping to gain from today's session?
What concerns and questions do you have?
Outline session agenda
Interim history
Dr. will examine to rule out possible syndromes associated with CL
We aren't expecting Dr. to find anything that makes him suspicious.

Medical History

Family History

Have you found out anything new about the family history?
Any new births, deaths, or diagnoses?

Cleft lip and palate

Before genetic counseling can be given, numerous syndromes must be excluded.
Definition: CL/CP due to a failure of the union of the frontonasal process of the face with the lateral maxillary prominence at about 3-4 weeks post conception (35 days gestation)
Classification of clefts
Nonsyndromic vs. syndromic
80% are unilateral, 20% bilateral, extends to the palate in 70% of unilateral cases and 85% of bilateral cases
Incomplete or complete (involving the lip and the anterior maxilla vs. involving the lip, anterior maxilla, hard and soft palate)
Unilateral clefting commonly occurs on the left (2x more frequently than right)
Male to female ratio is 2:1

Incidence

CL +/- CP occurs in 1:1000 Caucasian births, 1.7:1000 Asian births and 1:2500 AA
Isolated cleft lip and palate account for 25% of the cases of clefting
Left unilateral clefts, right unilateral clefts, and bilateral clefts occur at a 6:3:1 ratio.

Inheritance and Recurrence Risks

Most isolated occurrences are inherited multifactorially
Background risk: 0.1% (Harper)
RR- 3-7%, empiric
2-4% risk for offspring of an affected parent
2nd degree relative: 0.6% risk (Harper)

Risks

Specific factors increase the risk for CL/CP
- Severity of the trait (unilateral vs. bilateral; complete vs. incomplete)
- Number of affected relatives
- Sex affected (whether the person is of the sex opposite the most often affected)
- How closely the individual is related to the affected person)

Multifactorial Inheritance and Genetic counseling

A condition that is caused by several genes and the environment
Threshold model- baby inherits genes from both parents that increase the risk for cl/cp, then in combination with certain environmental factors the risk goes beyond the threshold level and the baby develops a cleft
Although there are multiple genes involved 3 predisposing genes have been identified.
- Explaining this to parents:
  - Children with cl/cp inherit genes in a random way from their parents
  - Parents cannot control which genes they pass on
  - Some of these genes contribute to facial development. We know that there are over 100 genes that contribute to the development of the lip and palate; there have been 3 genes found that we call predisposing genes- which means that in animal models we have been able to show that disruption or changes in this gene can lead to clefting.
  - when the lip forms in early development, cells migrate together to close the lip
  - Multiple genes tell those cells to move the way that they are supposed to
  - It takes more than genetic factors for someone to develop a cleft
  - Environmental factors play a big role.
  - We know some of the factors that interact with genes to cause clefts (smoking, alcohol, some medications) but we don't know them all.
  - There are some protective factors- folic acid
  - Timing is important, the lip is completely closed by the 35th day of gestational development (medicine or other factors after this time wouldn't have an effect on the lip)
Reassurance: you did everything within your control to have a healthy baby. Even if risk factors were present (smoking, drinking etc.) the mother should be reassured that even without these factors the baby could have been born with a cleft.
Currently there is no way to guarantee that a baby isn't born with a cleft. The best thing to do in future pregnancies is to avoid smoking, drinking, and certain medications (anticonvulsants, retinoic acid), and to take folic acid periconceptionally.

What's next?

Feeding issues? Make sure the baby is getting enough nutrition. Infants with isolated cleft lip (without cleft palate) seldom have problems feeding by breast or bottle.
Surgery: objective- to close the lip to create a pleasing face that will develop normally with minimal scarring.
Closure is performed when the baby is approximately 3 months old at weighs at least 10 pounds.
Correction of the nasal deformity is usually performed at the time of the lip repair.
Additional surgeries will be necessary to enhance the appearance of the lip and/or nose.
Initial surgery lasts ~2-3 hours and the hospital stay is usually 2-4 days.
- During this time special considerations are necessary for feeding and positioning. Elbows are restrained from bending. Positioning the child in an infant seat prevents rolling over and injuring the lip/nose. No pacifiers or nipples allowed. Fed with a special syringe feeder with a soft tube. It takes about 3 weeks for the wound to heal enough to stop these special precautions.
- The lip scar is initially red and swollen, but begins to mature and improve in appearance in ~6 months.
Isolated cleft lip- no expected problems with hearing or speech.
Possible problems with teeth…there can be missing or crooked teeth in the area of the cleft.

Follow up

Pediatrician for routine care
Contact craniofacial team- referral made, scheduled for the Nov. infant/toddler meeting- letter has been sent.
help with feeding, special bottles, positioning of the baby
The craniofacial team has a psychologist that can help with the emotional concerns of having a child with a facial cleft. Interested in scheduling an appointment?
Follow up with Dr. Billmier
and Dental services?

References

Smith's
Practical Genetic Counseling
Emery and Rimoin
Bender PL. Genetics of Cleft Lip and Palate. (2000). Journal of Pediatric Nursing. 15:4.
Clefts of the Lip and Palate. 1997. Tennessee Craniofacial Center.

Notes

The information in this outline was last updated in 2002.