New Insights into Kleefstra Syndrome: Report of Two Novel Cases with Previously Unreported Features and Literature Review.
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Published version
Embargoed until: 2222-01-01
Reason: Version Not Permitted
Embargoed until: 2222-01-01
Reason: Version Not Permitted
Volume
156
Pagination
127 - 133
DOI
10.1159/000494532
Journal
Cytogenet Genome Res
Issue
Metadata
Show full item recordAbstract
Kleefstra syndrome (KS) is a rare genetic condition resulting from either 9q34.3 microdeletions or mutations in the EHMT1 gene located in the same genomic region. To date, approximately 100 patients have been reported, thereby allowing the core phenotype of KS to be defined as developmental delay/intellectual disability, generalized hypotonia, neuropsychiatric anomalies, and a distinctive facial appearance. Here, to further expand the knowledge on genotype and phenotype of this condition, we report 2 novel cases: one patient carrying a 46-kb 9q34.3 deletion and showing macrocephaly never described in KS, and a second patient carrying a classic 9q34.3 deletion, presenting with a previously unreported skeletal feature (postaxial polydactyly of the right foot) and an unusual brain anomaly (olfactory bulb hypoplasia) observed via magnetic resonance imaging. Further, we provide a review of the current literature regarding KS and compare these 2 patients with those previously described, thereby confirming that the genotype-phenotype correlation in KS remains difficult to determine.