The microcephaly-lymphedema-chorioretinal dysplasia (MLCRD) syndrome is a distinct microcephaly syndrome. The hallmark features, microcephaly, chorioretinopathy, and lymphedema are frequently recognized at birth. Another clinical entity, the chorioretinal dysplasia, microcephaly and mental retardation syndrome (CDMMR) is a highly overlapping syndrome characterized by more variable lymphedema. Recently, heterozygous mutations in KIF11, a gene encoding a critical spindle motor protein of the Kinesin family, have been reported in individuals with MLCRD, and in individuals with CDMMR. This finding is suggestive of a single clinically variable spectrum. Here, we report on de novo novel mutations of KIF11 in five individuals with severe microcephaly, marked simplification of the gyral pattern on neuroimaging, bilateral chorioretinopathy, and developmental delay. Three patients had congenital lymphedema, and one had congenital bilateral sensorineural hearing loss. This report, therefore, further expands the clinical and molecular spectrum of KIF11-associated microcephaly.
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