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.

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.