Wide clinical variability in cat eye syndrome patients: four non-related patients and three patients from the same family.
A small supernumerary marker chromosome (sSMC) derived from chromosome 22 is a relatively common cytogenetic finding. This sSMC typically results in tetrasomy for a chromosomal region that spans the chromosome 22p arm and the proximal 2 Mb of 22q11.21. Using classical cytogenetics, fluorescence in situ hybridization, multiplex ligation-dependent probe amplification, and array techniques, 7 patients with sSMCs derived from chromosome 22 were studied: 4 non-related and 3 from the same family (mother, daughter, and son). The sSMCs in all patients were dicentric and bisatellited chromosomes with breakpoints in the chromosome 22 low-copy repeat A region, resulting in cat eye syndrome (CES) due to chromosome 22 partial tetrasomy 22pter→q11.2 including the cat eye chromosome region. Although all subjects presented the same chromosomal abnormality, they showed a wide range of phenotypic differences, even in the 3 patients from the same family. There are no previous reports of CES occurring within 3 patients in the same family. Thus, the clinical and follow-up data presented here contribute to a better delineation of the phenotypes and outcomes of CES patients and will be useful for genetic counseling.
Department of Morphology and Genetics, Universidade Federal de São Paulo, São Paulo, Brazil.
S I
SI
Belangero
A N X
AN
Pacanaro
F T
FT
Bellucco
D M
DM
Christofolini
L D
LD
Kulikowski
R S
RS
Guilherme
A
A
Bortolai
A R N
AR
Dutra
F B
FB
Piazzon
M C
MC
Cernach
M I
MI
Melaragno
D000328:Adult; D000782:Aneuploidy; D002648:Child; D002675:Child, Preschool; D025063:Chromosome Disorders / Q000235:genetics*; D002892:Chromosomes, Human, Pair 22 / Q000235:genetics; D044127:Epigenesis, Genetic; D005124:Eye Abnormalities; D005260:Female; D005500:Follow-Up Studies; D018628:Gene Dosage; D020022:Genetic Predisposition to Disease; D006801:Humans; D007223:Infant; D008297:Male; D055815:Young Adult