Subtelomeric 6p deletion: clinical, FISH, and array CGH characterization of two cases.
Thirty patients have been described with cytogenetically visible deletion of the short arm of chromosome 6. However, subtelomeric 6p deletion detected by subtelomeric specific probes has been reported only twice. We report two new patients with terminal 6p deletion detected by subtelomeric screening using fluorescence in situ hybridization (FISH). The two patients exhibited mental retardation, ocular abnormalities, hearing loss, and a characteristic facial appearance. Detailed FISH analyses with probes covering the distal 6p25 region estimated the size of the terminal deletions to approximately 5.5 Mb and approximately 4.8 Mb. Array-based comparative genomic hybridization (array CGH) was used to confirm the cryptic deletions. Most patients with subtelomeric defects lack a characteristic phenotype. However, some of the subtelomeric deletions result in a specific phenotype, which can direct the clinician towards the diagnosis. Submicroscopic 6p deletion appears to be a recognizable clinical phenotype, and this region should be thoroughly investigated with FISH probes, including at least a subtelomeric 6p probe and a probe covering FOXC1, for patients presenting with a characteristic facial appearance, ocular abnormalities, predominantly anterior-chamber eye defects, hearing loss, and mental retardation.
Le Caignec
Cédric
C
Service de Génétique Médicale, Centre Hospitalo-Universitaire, Nantes, France. lecaignec@hotmail.com
De Mas
Philippe
P
Vincent
Marie-Claire
MC
Bocéno
Michelle
M
Bourrouillou
Georges
G
Rival
Jean-Marie
JM
David
Albert
A
D000015:Abnormalities, Multiple / Q000235:genetics* / Q000473:pathology; D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002872:Chromosome Deletion; D002874:Chromosome Mapping; D002896:Chromosomes, Human, Pair 6 / Q000235:genetics*; D005124:Eye Abnormalities; D005145:Face / Q000002:abnormalities; D034381:Hearing Loss; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008607:Intellectual Disability / Q000473:pathology; D018895:Microsatellite Repeats; D009693:Nucleic Acid Hybridization / Q000379:methods; D016615:Telomere / Q000235:genetics