Oro-facial Clefts in Alberta 1980-2004 Inclusive

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Barbara Sibbald MSc¹ and R. Brian Lowry MD, DSc ^1,2

Alberta Congenital Anomalies Surveillance System, Health Surveillance, Alberta Health and Wellness ¹ and Department of Medical Genetics , Alberta Children’s Hospital and University of Calgary, Calgary, Alberta, Canada ²

Introduction

The Alberta Congenital Anomalies Surveillance System (ACASS) is a population based semi-active system that gathers data on congenital anomalies among Alberta births to Alberta residents up to one year of age. ACASS has been in operation since 1980, collecting data on all live births and stillbirths and in 1997 added the ascertainment of foetal (<20 weeks or <500 g) anomalies.

Multiple ascertainment sources are used including: Physician’s Notice of Live Birth (PNOB), Stillbirth Certificate, Medical Certificate of Death (MCD) and Congenital Anomalies Reporting Form (CARF). The PNOB, MCD and Stillbirth Certificates are submitted by Vital Statistics. The CARFs are submitted by: Health Records Technologists in all of the hospitals in the province, the provincial metabolic screening programme, cytogenetics labs, genetics clinics and post partum units. Letters are sent to the attending physician or physician responsible for ongoing care to clarify any unclear or queried diagnoses or to request pathology reports where applicable

Methods

We reviewed all notifications of oro-facial clefting to ACASS from 1980 to 2004 inclusive and calculated the rates per 1000 total births for cleft lip plus or minus cleft palate (CL+/-CP) and cleft palate (CP) alone. As is standard practice, CL+/-CP and CP alone were analysed separately because of their embryologically distinct origins (1). We examined the data by year, maternal age, sex and whether or not the defect was isolated. We included the year 2004 even though the data might not be complete given our 1 year ascertainment period and waiting for clarification on some cases. Until 2003 we used the British Paediatric Association adaptation of ICD-9 for coding anomalies (749.0(CP), 749.1(CL) and 749.2(CL+P)) and since then we have used the Royal College of Paediatrics and Child Health adaptation of ICD-10 (Q35 (CP), Q36 (CL) and Q37 (CL+P)).

Results

There are approximately 40,000 births per year in Alberta and approximately1500 cases with congenital anomalies are entered into the ACASS database each year. Over the past 25 years 1931 cases among live births and stillbirths of orofacial clefts have been ascertained by the surveillance system, an average of 77 per year.

Between 1997 and the end of 2004 we received 518 foetal notifications (i.e. not registered by Vital Statistics as a live birth or stillbirth), 23 of which had orofacial clefts (21 CL+/-CP; 2 CP alone). If we include these, our total ascertainment is 1954 cases.

CL+/-CP

Over the past 25 years, the average rate of CL+/-CP has been 1.14/1000 total births (range 0.89/1000 to 1.47/1000) or 1/877 total births. No significant trend in rates over time has been observed for all CL+/-CP (χ 2 trend 0.59, p = 0.4424), similarly for isolated CL+/-CP (Figures 1 and 2).

Of all CL+/-CP, 64% were male (M:F 1.80:1) and of isolated cases, 66% were male (M:F 1.94:1). Just under 75% of cases of all CL+/-CP were isolated (n=884).

Of the CL+/-CP cases with multiple malformations (n=301) (defined as 2 or more malformations), approximately 31% were part of a recognized pattern of malformations or had a cytogenetic abnormality. See Appendix 1 for a list of recognized patterns of multiple malformations.

Figure 1   

Figure 2

CP alone

The average rate for CP alone from 1980-2004 inclusive has been 0.76/1000 total births (range 0.48/1000 to 1.14/1000) or 1/1316). There has been a statistically significant upward trend over the 25 years (χ 2 trend 7.52, p = 0.0061) for all CP however this disappears for isolated CP (Figures 3 and 4).

Fewer males than females were affected with CP alone (48%) (M:F 0.97:1) and in isolated cases, the percentage did not change. Just over 41% of all CP were isolated (n=320).

Pierre Robin Sequence was counted in the multiples and categorized as a syndrome/sequence. Of the CP cases with multiple malformations (n=449), 60.58% were part of a recognized syndrome/sequence or had a cytogenetic abnormality. Pierre Robin Sequence with no other anomalies associated with it accounted for 17.6% (n=79) of the multiples. The most common cytogenetic anomaly was Trisomy 13. See Appendix 2 for a list of recognized patterns of multiple malformations.

Figure 3

Figure 4
All Orofacial clefts

Terminations of pregnancy do not influence the overall rates to any great extent (see Figures 1-3), especially with cleft palate alone. Of interest, there does not seem to be a decrease in the rates of CL+/-CP or CP alone since the introduction of folic acid fortification of flour but if one examines isolated CP there might be a suggestion of a decrease in rates since 1998 (Figure 4).

Maternal Age

As you can see from Figures 5 and 6, there is an increase in the rate of clefting when the maternal age is 35 years or greater for both CL+/-CP and CP alone. It is interesting to note that for CL+/-CP, there is also a higher rate among younger mothers.

Figure 5

Figure 6

Summary

In summary, oro-facial clefting anomalies are relatively common in Alberta (CL+/-CP 1.14/1000 total births; CP alone 0.76/1000 total births). More males are affected with CL+/-CP and more females with CP, alone which is consistent with the literature (2,3). Of interest, clefting rates, both CL+/-CP and CP alone, rose with increasing maternal age and in the cases of CL+/-CP there was an increased rate among younger mothers as well. Although it appears that folic acid fortification has had no effect on clefting rates, there is a suggestion that the rates might be decreasing among cases of isolated CP. Further analysis is warranted.

References

1. Moore K, Persaud TVN. The developing human: clinically oriented embryology.
   7 th ed. Philadelphia : W.B. Saunders; 2003
2. Mossey P, Little J. Epidemiology of oral clefts: an international perspective. In: Wyszynski, D ed. Cleft lip and palate: from origin to treatment. Oxford : Oxford University Press; 2002. p. 127-58
3. Vallino-Napoli L, Riley M, Halliday J. An epidemiologic study of isolated cleft lip, palate, or both in Victoria , Australia from 1983-2000. Cleft PalateCraniofac J, 2004 Mar; 41(2): 185-94

Appendix 1 Recognized Patterns of Multiple Malformations
CL+/-CP 1980-2004

Syndromes, Associations and Multiple Anomaly Groupings (n=41) (number of cases in brackets)
Acardia (1) Agnathia (1) Amniotic Bands (13) Asymmetric Crying Facies (1) Body Wall Complex (4) CHARGE (1) Femoral facial (1) First Arch Syndrome (1) Foetal Alcohol (1) Foetal Hydantoin (1)	Frontonasal Dysplasia (2) Fryns (1) Goldenhar (3) Heterotaxy (2) Hydrolethalus (1) Kallman (1) Pseudo Trisomy 13 (2) Septo-Optic Dysplasia (1) Van der Woude (3)
Cytogenetic (n=53) Trisomy 13 (22) Trisomy 18 (15) Trisomy 21 (2)
Other deletions, translocations, mosaics, markers (14)

Appendix 2 Recognized Patterns of Multiple Malformations
CP 1980-2004

Syndromes, Associations and Multiple Anomaly Groupings (n=214) (number of cases in brackets)
Acrocallosal (1) Acrofacial dysostosis(1) Amniotic Bands (1) Apert (7) Beckwith Wiedemann (2) Blackfan Diamond (1) Bowen Conradi (2) Cat Eye (1) Caudal regression (2) Cerebro-costo-mandibular (1) CHARGE (1) Coffin Siris (1) Cornelia de Lange (5) Cyclops (1) EEC (1) FAS (5) Frontonasal dysplasia (1) Fryns (1) Goldenhar Gorlin/Goldenhar (4) Kabuki (1) Klippel Feil (1)	Kniest Dysplasia (1) Meckel Gruber (3) Moebius (6) Multiple Pterygium (1) Nager (1) Neu Laxova (1) Noonan (1) Oral facial digital (1) Pena Shokier (1) Pierre Robin (144) Rubella (1) Saethre Chotzen (1) Smith Lemli Opitz (3) Sprintzen/VCF (3) Stickler (4) Treacher Collins (4) Valproate (1) Vater (2) Whistling Face (1)
Cytogenetic (n=58) Trisomy 13 (13) Trisomy 18 (7) Trisomy 21 (2)
Other deletions, translocations, mosaics, markers (36)

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