“…Recent literature agrees that the optimal tissue sample is cultured fibroblasts derived from a skin biopsy because other easily obtainable tissues (such as saliva, buccal swabs, or nails) can be contaminated with blood cells. 4,24 Ancillary testing for HHMS Telomere length studies are a sensitive and specific test for the diagnosis of telomere biology disorders (TBDs) and can be a predictor of disease severity. Similarly, chromosome breakage studies may aid in the diagnosis of suspected chromosome instability syndromes, including Fanconi anemia, ataxia telangiectasia, or Nijmegen breakage syndrome.…”