Epidemiology and genetics of microtia-anotia: a registry based study on over one million births.

Abstract

The epidemiology and genetics of microtia-anotia (M-A) were studied using data collected from the Italian Multicentre Birth Defects Registry (IPIMC) and that mothers with chronic maternal insulin dependent diabetes were at significantly higher risk for having a child with M-A. MMI with M-A had higher rates of prematurity, low birth weight, reduced intrauterine growth, and neonatal mortality than infants with isolated M-A and controls. Babies with isolated M-A had, on average, a lower birth weight than controls; the difference was higher for females. The analysis of pedigrees and familial cases suggests an autosomal dominant trait with variable expression and incomplete penetrance in a proportion of cases, or a multifactorial aetiology. Three cases had consanguineous parents, but the absence of M-A among previous sibs does not support autosomal recessive inheritance. (J Med Genet 1995;32:453-457) Microtia and anotia (M-A) are malformations of the auricle ranging from a measurably small external ear with minimal structural abnormality, to an ear with major structural alteration, to total absence of the ear.'

Prevalence at birth of congenital abnormalities of external ears in Hungary

“…The mild male excess of cases with isolated ear CAs in the study was in agreement with the results of some previous studies [11,13,15,[18][19][20][21][22][23], though the cases with isolated microtia/anotia in the Italian registry did not show a male predominance [24]. The strong male excess in cases with unclassified multiple ear CA is worth mentioning, because in general previous studies did not have strict differentiation between cases with isolated and multiple ear CAs.…”

“…The obvious predominance of unilateral cases and among them a slight right side excess in cases with isolated microtia/anotia in our study corresponded to the previous observations in other studies/countries [11,13,15,[18][19][20][21][22][23][24][25].…”

“…Similar findings were found in other studies, e.g. 13%-22% of bilateral cases had the combination of microtia and anotia in the Italian registry [24] and in the international collaborative study based on CA registries [11] indicating their common origin. On the other hand it is worth mentioning the significant difference between the predominance of unilateral cases with isolated and multiple ear CAs (93.4% vs. 62.2%) in our study.…”

Congenital Unilateral microtia in a neonate of hypothyroid, hypertensive and diabetic mother – a rare case report

“…There are few published studies on microtia -anotia frequency. The birth prevalence estimates vary greatly among countries ranging from 0.8 to 17.4 per 10, 000 (3) . Anotia accounts for 13-22% of all cases of microtia and anotia combined (4) .…”

“…It can be an isolated finding or it may be associated with goldenhar syndrome (most severe manifestation of occulo-auriculo-vertebral spectrum). Treacher Collis syndrome, Oromandibulo-facial dysostosis, Meir Gorlin syndrome, Thalidomide embryopathy (3) , Diabetic Embryopathy (5) , Holoprosencephaly, Fryns syndrome etc. (6) .…”