Two families with phenotypically different hereditary low frequency hearing impairment: longitudinal data and linkage analysis.

Two families with low frequency hearing impairment have been described previously. Family A (Danish) presented a sensorineural hearing impairment most pronounced for frequencies below 2 kHz and a pedigree typical for an autosomal dominant trait with complete penetrance (Königsmark type). Family B, originating from the Faroe Islands, showed conflicting audiological test results, making a valid classification impossible. The pedigree suggested autosomal dominant inheritance with incomplete penetrance. The objectives of the present study are to acquire longitudinal audiometric data, to clarify the mode of transmission, and to localize the mutant gene by reevaluation of the two families. The methods used are evaluation of the family history, audiological examination and linkage analysis. In family A, update of the pedigree fitted the assumption of an autosomal dominant mode of transmission. In six examined subjects audiological data were available from the previous study. The median progression over a 13-21-year period was 13.8 dB HL for the thresholds, averaged across 0.5, 1, 2 and 4 kHz and 17.5 dB HL for the thresholds, averaged across 2 and 4kHz. In family B, the probable mode of transmission is autosomal dominant with reduced penetrance. In this family no progression of the hearing impairment was found. Linkage analysis of family A showed a lod score of 3.53, indicating significant linkage to the loci DFNA6 and DFNA14 on chromosome 4, previously found to be involved in low frequency hearing impairment. Family B was not linked to the region on chromosome 4, further adding to the genetic heterogeneity in low frequency sensorineural hearing impairment.

The soil fungus Chaetomium in the human paranasal sinuses.

Chaetomium is a soil fungus of which more than 180 species are now known. Most species cause degradation of cellulose-rich substrates, such as components in soil, straw or wood. Growth of Chaetomium globosum is often stimulated in the presence of Aspergillus fumigatus, which excretes such compounds as sugar phosphates and phospho-glyceric acid. A 73-year-old woman, with long-standing pain and secretion from her left maxillary sinus, was admitted to hospital where an infundibulectomy was performed. Histological examination showed necrotic material with hyphae of A. fumigatus and perithecia of Chaetomium sp. The latter fungus is rarely pathogenic to man.

Bilateral carcinoma of the external auditory meatus.

A 65-year-old woman had suffered for two months from bilateral tinnitus and discharge, pain in the right ear, and loss of hearing. Biopsy showed carcinoma of the squamous type on both sides. Tomography revealed bone destruction on the right. The patient was treated with radiotherapy. Two months after treatment, tomography showed tumour regression on the right side, but progression on the left. The literature on this subject is reviewed.