Prenatal diagnosis of fetal craniofacial dysmorphology continues to be a challenge for the clinician. Unless there is an obvious abnormality detected by molecular methodology or cytogenetics, the degree of dysmorphology is not easily determined. We have shown in the past that accurate fetal cephalometry by ultrasound is feasible during the 16th week of gestation. Normal standards describing the fetal craniofacial growth have been reported. We hypothesized that craniofacial cephalometry is able to detect prenatal craniofacial dysmorphology and provide a measurement of the degree of abnormality seen, by calculating the fetal dysmorphic index (craniofacial pattern variability index). Sigma Z or pattern variability represents the standard deviation of the Z-scores which form a set of craniofacial measurements for each individual corrected for gestational age. We report here the findings in 5 individuals referred to us for suspicion of fetal craniofacial abnormalities, three of them clearly showed abnormal PVI's, and two were borderline. After birth, all infants were examined by a certified dysmorphologist. In 2 patients, no significant anomalies were noticed, however, three of them were diagnosed with three different conditions: (1) Fetal Alcohol syndrome; (2) Crouzon syndrome; and (3) Thanatophoric dysplasia. Table

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Conclusion: These preliminary results indicated that fetal craniofacial dysmorphology can be detected in utero by using craniofacial cephalometrics. Sigma-Z or pattern variability index is a useful indicator of craniofacial dysmorphology. Additional studies are required in order to accumulate data that would predict the accuracy of this relatively new application of prenatal ultrasonography.