Academicians are more likely to share each other's toothbrush than each other's nomenclature [Cohen, 1982]

Congenital limb deficiency classification and nomenclature: The need for a consensus

After the thalidomide epidemic in the early 1960s, many jurisdictions developed congenital anomaly surveillance systems. Congenital limb deficiencies can act as indicators of potential teratogens. The classification of congenital limb deficiencies is essential to determine the precise cause or causes of this anomaly. This article describes the different terminology and classification that have been used over time and the need for a consensus. While there are a variety of studies examining the epidemiology and etiology of congenital limb deficiencies, there is an inconsistent use of terminology and classification which makes comparisons between studies challenging. © 2016 Wiley Periodicals, Inc.

Limb deficiencies in newborn infants

OBJECTIVE

The prevalence rate of all types of limb reduction defects in general and those that potentially are caused by vascular disruption in particular is needed to provide a baseline for the evaluation of infants who are exposed in utero to teratogens that cause vascular disruption. The objective of this study was to determine this prevalence rate.

METHODS

All infants with any limb deficiency among 161 252 liveborn and stillborn infants and elective terminations were identified in a hospital-based Active Malformations Surveillance Program in Boston in the years 1972 to 1974 and 1979 to 1994. An extensive search was made to identify infants who were missed by the Surveillance Program; an additional 8 infants (7.3% of total) were identified. The limb reduction defects were classified in 3 ways: 1) by the anatomic location of the defect, that is longitudinal, terminal, intercalary, etc; 2) for infants with absence/hypoplasia of fingers or toes, a tabulation of which digit or digits were affected; and 3) by apparent cause.

RESULTS

The prevalence rate for all types of limb deficiency was 0.69/1000. The apparent causes included single mutant genes, familial occurrence, and known syndromes (24%); chromosome abnormalities (6%); teratogens (4%); vascular disruption (35%); and unknown cause (32%).

CONCLUSIONS

A hospital-based surveillance program can be used to establish the prevalence of limb reduction defects, if ascertainment is extended to include elective terminations for fetal abnormalities. An apparent cause can be established for most limb defects when the clinical findings are used rather than reliance only on the International Classification of Diseases, Ninth Revision, codes of the discharge diagnoses. The prevalence rate of limb reduction defects as a result of presumed vascular disruption was 0.22/1000.