Taste thresholds in mothers of children with Dow's syndrome

[Evaluating function and disorders of taste]

In a first anatomical section the peripheral gustatory pathways, their central connections, nuclei and cortical projections are discussed. It is evident, that the gustatory fibres from the posterior part of the tongue run in the IX nerve and those from the soft palate reach the medulla oblongata via the petrosal and facial nerve. For the anterior part of the tongue there obviously exists only one gustatory pathway via the chorda tympani-facial nerve. About the further central pathways of taste fibres is much less known. In a second part the methods of taste testing with different taste solutions and the electrogustometry are described. Their practical use and the pitfalls of testing are considered. The disorders of the taste sense compose a third part. Genetic and endocrine abnormalities as well as the side effects of drugs and radiotherapy and the destruction of taste nerves may lead to gustatory deviations. The possibility of central gustatory disorders, especially the combined loss of taste and smell as a result of trauma are mentioned. A chapter dealing with the therapy of taste disorders and a short outlook on the genetic aspects of this oral sense complete this review.

RESEARCH IN THE ETIOLOGY OF DOWN'S SYNDROME. INTRICACIES AND PITFALLS

Cytological studies have shown that Down's syndrome (“ mongolism ”) is the result of a chromosomal anomaly which occurs either in one of the parent's germ cells or at a very early stage in (embryonic) development of the affected individual. The chromosomal anomaly involves the occurrence of a third number 21 chromosome, in addition to the normal complement of two, either separately (i. e., trisomy-21) or attached to one of the other acrocentric chromosomes (i. e., translocation to one of the chromosomes numbered 13-15 or 22 — Denver Report, 1960). Epidemiological studies have indicated that numerous factors are related to, and may affect, incidence of the chromosomal anomalies resulting in Down's syndrome. Studies by Collmann and Stoller (1962a, b) imply fluctuations of annual incidence with a 5-6 year periodicity, a higher incidence in urban compared to rural areas and a clusteting of affected births in certain geographic regions. Collmann and Stoller postulated an “ infectious agent, probably a virus ”, to account for their data. No connection, however, can yet be drawn between such a hypothesis and the established cytogenetic anomaly. Periodic fluctuations in incidence, which are characteristic of recurrent epidemics (Gordon, 1962), have also been reported for congenital anomalies other than Down's syndrome, such as anencephaly, spina bifida, and hydrocephaly (Collmann and Stoller, 1962b; Guthkelch, 1962; Alter, 1962; Slater, Watson and McDonald, 1964).