Hemihyperplasia/hemihypertrophy in adolescents: prospective international study

: Aim The reported incidence of isolated hemihyperplasia (IH) has a very wide range (from 1:13,000 to 1:86,000 live births) and further clarification is needed. We hypothesized that a survey of the birth prevalence of IH among newborn infants may underestimate the incidence of IH by overlooking late-onset cases. Methods The prospective international multicenter study utilized the two-steps selection tool for an anonymous survey of volunteers of 15-18 years old. The initial step was "three measurements-three questions" screening, or "face-palms-calves survey". The subsequent step was an in-depth assessment of selected cases to exclude localized, lesional and syndrome-related cases as well as body asymmetry within normative range and to select suspected cases of IH. This step included measurements of various anatomical regions and a subsequent questionnaire. The participants that were selected in a risk group were advised to refer to medical institutions for clinical, genetic and instrumental investigation. Results Out of 6000 of selected participants (male, M 3452, female, F 2548), 229 (3.82%) were selected for detailed investigation and 57 (0.95%) were assigned to the risk group. Only 36 of them were actually referred to medical institutions and in two cases the diagnosis of IH was confirmed. Conclusion Our survey indicated the prevalence of IH at the age of adolescence as approximately 1:3000. While IH is a hereditary genetic disorder, it may not be detected in newborns and infants and the true prevalence of the disease can be estimated if older age children are screened.