Deardorff et al. (2007) identified a patient with a variant form of Cornelia de Lange syndrome (CDLS) who carried a mutation in the SMC3 gene. The patient had arched eyebrows, synophrys, and long eyelashes, thin lips, small hands ... Deardorff et al. (2007) identified a patient with a variant form of Cornelia de Lange syndrome (CDLS) who carried a mutation in the SMC3 gene. The patient had arched eyebrows, synophrys, and long eyelashes, thin lips, small hands and feet, proximally set thumbs, fifth finger clinodactyly, restriction of elbow movements, and hirsutism, in addition to high nasal bridge and high palate. He lacked brachycephaly, low anterior hairline, anteverted nostrils, long philtrum, downturned corners of the mouth, micrognathia, and hearing loss. He was employed in a supervised position in a greenhouse. The authors noted that both SMC3 and SMC1A (300040) mutation-positive patients exhibit very mild facial dysmorphism, no absence or reduction of limbs or digits, and no other major structural anomalies.
The patient identified by Deardorff et al. (2007) with mild variant CDLS carried a de novo 3-bp deletion in the SMC3 gene (606062.0001). Deardorff et al. (2007) noted that the milder CDLS phenotype had been reported repeatedly and ... The patient identified by Deardorff et al. (2007) with mild variant CDLS carried a de novo 3-bp deletion in the SMC3 gene (606062.0001). Deardorff et al. (2007) noted that the milder CDLS phenotype had been reported repeatedly and accounts for approximately 20 to 30% of the CDLS population. The data indicated that SMC3 and SMC1A mutations contribute to approximately 5% of cases of CDLS, resulting in a consistently mild phenotype with absence of major structural anomalies typically associated with CDLS, and in some instances, resulted in a phenotype that approaches that of apparently nonsyndromic mental retardation.