Article Text

Download PDFPDF
Epidemiology and genetics of microtia-anotia: a registry based study on over one million births.
  1. P Mastroiacovo,
  2. C Corchia,
  3. L D Botto,
  4. R Lanni,
  5. G Zampino,
  6. D Fusco
  1. Department of Paediatrics, Catholic University, Rome, Italy.


    The epidemiology and genetics of microtia-anotia (M-A) were studied using data collected from the Italian Multicentre Birth Defects Registry (IPIMC) from 1983 to 1992. Among 1,173, 794 births, we identified 172 with M-A, a rate of 1.46/10,000; 38 infants (22.1%) had anotia. Of the 172 infants, 114 (66.2%) had an isolated defect, 48 (27.9%) were multiformed infants (MMI) with M-A, and 10 (5.8%) had a well defined syndrome. The frequency of bilateral defects among non-syndromic cases was 12% compared to 50% of syndromic cases (p = 0.007). Among the MMI only holoprosencephaly was preferentially associated with M-A (four cases observed upsilon 0.7 expected, p = 0.005). No significant variations were identified in the prevalence of non-syndromic cases by geographical area (range 0.62-2.37/10,000 births) or by five month time periods (range 0.21-2.58/10,000 births), nor was there evidence of time trends. When M-A cases were compared to controls, we found that mothers with parity 1 had a higher risk of giving birth to an MMI with M-A, 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.

    Statistics from

    Request Permissions

    If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.