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An autosomal dominant form of familial laryngeal abductor paralysis is linked to a 5-centiray region on chromosome 6q16 surrounding D6S1021.

We conducted a study oflipid peroxidation as a marker of age-related f ree-radical damage in the human larynxthe first study of its kind. A colorimetric assay fo r malondialdehyde (MDA) and 4-hydroxy-2-nonenal (4-HNE) was p erform ed on extrac ts taken from thyroarytenoid muscle harvested fro m f resh cadaveric laryngeal specimens. Levels of MDA and 4-HNE were measured by spec tropho tometry. Correlation studies were performed by linear regression analysis. We fo und that MDA levels in human thyroarytenoid muscl e appeared to increase with age while 4-HNE levels showed a slight decrease with age. Ourfi ndings are consistent with those of previous studies of other organ systems and indicate that there is a need f orfu rther study offree-radical damage and the effects of aging on the human larynx and on voice production.

Objective: To determine whether age-related mitochondrial DNA mutations occur in the human larynx. Study Design: Genetic study of cadaveric larynx specimens. Methods: Vocal fold mucosa, thyroarytenoid muscle, and cricoarytenoid joint tissue were harvested from 13 fresh postmortem larynges (age range, 2 d-82 y). DNA was extracted from each sample, and the polymerase chain reaction (PCR) was used to amplify a target DNA sequence resulting from the common age-associated, 4977-base-pair (bp) mitochondrial DNA deletion. PCR products were visualized by agarose gel electrophoresis. Automated sequencing determined the sequence of identified PCR products. Subjects: Thirteen cadaveric larynges were obtained through the University of Kentucky Medical Center (Lexington, KY). Specimens from patients with a history of head and neck cancer, previous laryngeal trauma, or surgery were excluded. Results: Strongly positive bands were identified in samples from three individuals. Weaker bands were seen in samples from four other samples. No band was noted from the two pediatric larynges. Different band patterns were seen among the three different tissue sites in the larynges with positive PCR products, but no consistent pattern was seen. Sequencing of the identified PCR products from selected samples confirmed that they were products of the age-associated, 4977-bp mitochondrial DNA deletion. Conclusions: An age-associated mitochondrial DNA deletion was detected in several postmortem human larynges. Its presence seemed to increase in appearance with age. In the larynges in which the deletion occurred, there were individual regional differences in the occurrence of the deletion, but no consistent pattern was noted across all individuals who carried the deletion.

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