3p deletion detected on telomere screening.
We were very interested in the review article on telomeres by de Vries et al.
The authors comment that all of the 3p terminal deletions reported in the literature were microscopically visible, except for two siblings with an unbalanced familial translocation. We have recently seen a child where we detected a 3p deletion on telomere analysis that was not visible by routine cytogenetics. The child in question was born at 38 weeks weighing 7lb 4 oz. At birth she had dislocated hips and talipes equinovarus. She had marked dimples around her ankles and elbows and deep palmar creases. She had notable facial asymmetry with a right ptosis, mandibular asymmetry and a slightly small right ear. She was a poor feeder requiring a gastrostomy and on follow-up it became clear that she was globally developmentally delayed. Cardiac evaluation revealed atrial and ventricular septal defects. She was referred to the clinical genetics service at 14 months of age when she was noted to have trigonocephaly. She also had small finger and toe nails, especially of the 5th fingers and toes. An MRI scan showed some degree of frontal lobe atrophy and slightly thin corpus callosum.
This case illustrates the value of telomere screening in selected patients. Trigonocephaly has not been a clinical feature highlighted in the discussion about the indications for telomere screening but given the number of chromosome abnormalities that have been associated with this finding, we believe that those children with developmental delay and trigonocephaly should have telomere studies performed if the conventional cytogenetic analysis is normal and there is no other likely cause such as anticonvulsant exposure in utero.
(1) De Vries BBA, Winter R, Schinzel A, van Ravenswaaij-Arts C. Telomeres: a diagnosis at the end of the chromosomes . J Med Genet 2003;40:385-398.