The penta-X syndrome.
A child is presented with a 49,XXXXX chromosomal constitution bringing to 12 the total number of children described with this karyotype. Comparison of this child's features with previously reported cases indicates a clinically recognisable specific pattern of malformations referred to as the penta-X syndrome. X chromosome replication studies using BrdU labelling in the patient's cells clearly showed that the four presumably inactive X chromosomes were late replicating but not in a strictly synchronous fashion.
D000015:Abnormalities, Multiple / Q000235:genetics*; D001973:Bromodeoxyuridine; D002871:Chromosome Banding; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007621:Karyotyping; D010641:Phenotype; D012729:Sex Chromosome Aberrations / Q000235:genetics*; D012730:Sex Chromosomes / Q000648:ultrastructure; D013577:Syndrome; D014960:X Chromosome / Q000648:ultrastructure
D001973:Bromodeoxyuridine