Figure 1.

Cytogenetic analysis of patient. A) 45,XX,i(13)(q10) chromosomal karyotype of proband, showing the presence of a single metacentric chromosome consisting of two copies of the patient's chromosome 13 joined at the centromere (arrow), B) Composite of derivative 13 homologues from three metaphase spreads with centromeres indicated by arrows, C) Composite of acrocentric homologues hybridized with alpha satellite DNA probe for centromeres of chromosomes 13 and 21, demonstrating the presence of a large centromere on the isochromosome 13, D) Interphase cell with alpha satellite DNA probe for centromeres of chromosomes 13 and 21. Arrow points to large likely signal of the isochromosome 13.