{'fraction_non_alphanumeric': 0.029530978575564564, 'fraction_numerical': 0.01563404748118124, 'mean_word_length': 5.830039525691699, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Subtelomeric chromosome rearrangements in children with idiopathic mental retardation: applicability of three molecular-cytogenetic methods.

AIM
To identify cryptic subtelomeric rearrangement, a possible cause of idiopathic mental retardation by means of multiprobe telomere fluorescent in situ hybridization (T-FISH).


METHODS
Hundred patients (median age 3.0 years) with mental retardation and dysmorphic features were screened using specific T-FISH probes. Multiplex ligation-dependent probe amplification and comparative genomic hybridization were used for the confirmation of results.


RESULTS
Telomere fluorescent in situ hybridization revealed 11 subtelomeric abnormalities in 10 patients (10%; 95% CI, 5.0-17.5). Four of these had only a deletion of subtelomere 2q, which was apparently a normal variant. Among 6 true aberrations (6%; 95% CI, 2.5-12.5) we found 2 de novo subtelomeric deletions and 4 unbalanced subtelomeric rearrangements (one de novo). All clinically significant subtelomeric rearrangements were confirmed by multiplex ligation-dependent probe amplification. Comparative genomic hybridization was used to investigate the whole genome of patients in whom a subtelomeric anomaly was found, confirming some, but not all subtelomeric rearrangements.


CONCLUSION
Telomere fluorescent in situ hybridization and multiplex ligation-dependent probe amplification are both very useful and interchangeable methods for detection of unbalanced chromosome rearrangements, but T-FISH also detects balanced rearrangements. In our experiment the resolution power of comparative genomic hybridization was too low for subtelomeric screening compared with T-FISH and multiplex ligation-dependent probe amplification.