Craniofacial microsomia, associated congenital anomalies, and risk factors in 63 cases from the Alberta Congenital Anomalies Surveillance System.

OBJECTIVES: To report associated congenital anomalies with unexplained craniofacial microsomia (CFM) and the phenotypic overlap with other recurrent constellations of embryonic malformations (RCEM), and to assess prenatal and perinatal risk factors STUDY DESIGN: This is a retrospective cross-sectional study. Cases with CFM, delivered between January 1, 1997, and December 31, 2019, were abstracted from the population-based Alberta Congenital Anomalies Surveillance System. Livebirths, stillbirths, and early fetal losses were reviewed to include all types of pregnancy outcomes along the spectrum of this condition. Prenatal and perinatal risk factors were compared with the Alberta birth population to assess differences between the two groups.

RESULTS: There were 63 cases with CFM, yielding a frequency of 1 per 16949. There was a high rate of cases (65%) with anomalies outside the craniofacial and vertebral regions. Congenital heart defects were the most common (33.3%). A single umbilical artery was found in 12.7% of cases. The twin/triplet rate of 12.7% was significantly higher than the Alberta rate of 3.3% (p<0.0001). There was an overlap with a second recurrent constellations of embryonic malformations (RCEM) condition in 9.5% of cases.

CONCLUSIONS: Although CFM is primarily a craniofacial condition, the majority of cases have congenital anomalies affecting other systems requiring additional assessments ,including an echocardiogram, renal ultrasound, and a complete vertebral x-ray. The high rate of an associated single umbilical artery raises the possibility of a related etiological mechanism. Our findings support the proposed concept of RCEM conditions.