Subtelomeric rearrangements detected by FISH in three of 33 families with idiopathic mental retardation and minor physical anomalies

Telomeres: a diagnosis at the end of the chromosomes

“…A 5 year old, severely mentally retarded boy with microcephaly, facial dysmorphism (high forehead, flat occiput, hypertelorism, epicanthic folds, short nose with bulbous tip, flat philtrum, open mouth with downturned corners), fifth finger camptodactyly, and talipes valgus with absence of the fifth toe nails, and a 46,XY,der(13)t(4;13)(p16.3;q34)pat was reported by Helias-Rodzewicz et al 30 His severely mentally retarded father's sister had similar clinical features and the same chromosomal abnormalities.…”

“…A der(2)t(2;7)(q73;q36) was detected in a severely cognitively retarded 3 year old boy with facial dysmorphism (prominent forehead, downward slanting palpebral fissures, arched eyebrows, long eyelashes, small mouth with short philtrum and thin upper lip), a few café au lait spots, pectus carinatum, and talipes equinovarus. 30 Mildly mentally retarded patients with 2qter deletions and an inconsistent clinical phenotype have been reported [31][32][33] and Figure 1 Clinical photographs of various patients with subtelomere deletions.…”

The Use of Molecular Cytogenetic Techniques for the Identification of Chromosomal Abnormalities

“…The development luorescence in situ hybridization (FISH) technique increased the resolution of visualization of the chromosome rearrangements which is at the submicroscopic level [12,21]. The FISH is applied on metaphase chromosomes, interphase nuclei, ixed tissues or cells and solid tumour samples [22].…”

“…The sub-telomeric deletions were associated with the severe problems, which include mental retardation, developmental delay, and this terminal deletions cannot detect with the conventional cytogenetic techniques. The sub-telomeric FISH analysis is the appropriate technique to evaluate the abnormalities [10,11,21]. Some exceptions occur like loss of the short arm material from acrocentric chromosomes during the formation of Robertsonian translocations has no impact on phenotype [1].…”

Oncogenic Remodeling of the Three-Dimensional Organization of the Interphase Nucleus: c-Myc Induces Telomeric Aggregates Whose Formation Precedes Chromosomal Rearrangements

“…Moreover, nuclear remodeling of telomeres may not only play a role in cancer but also in the generation of mental retardation and malformations in which subtelomeric regions are involved. 48 …”