Uthra Mohan BSc, Presenter: Nothing to Disclose

Phyllis Glanc MD, Abstract Co-Author: Nothing to Disclose

Sarah Keating, Abstract Co-Author: Nothing to Disclose

David Chitayat MD, Abstract Co-Author: Nothing to Disclose

Ants Toi MD, Abstract Co-Author: Nothing to Disclose

Karen Chong MD, Abstract Co-Author: Nothing to Disclose

George Tomlinson, Abstract Co-Author: Nothing to Disclose

The purpose of this study is to determine the distribution of various fetal skeletal disorders in a tertiary care centre, based on the 2006 Nosology and Classification of Genetics Skeletal Disorders1. The study will provide additional information on rare skeletal disorders and will further characterize pathologic and radiological features of these disorders.

A retrospective review of 1806 perinatal autopsies from 2002-2009 at Mount Sinai Hospital, Toronto, ON was performed. The study population consisted of stillborns fetuses in their second and third trimesters as well as live born infants who died shortly after birth. Pathological, genetic, clinical and radiological information were reviewed and utilized to achieve a final diagnosis.  

Of the 1806 autopsies performed, 91 received a final diagnosis of a skeletal disorder and encompassed 15 out of the 37 groups according to the 2006 Nosology classification1. The frequency of skeletal disorders was 1:20 autopsies. Out of the 91 cases, 75 (82.5%) had a complete autopsy (photographs, x-rays, gross physical and histopathological analysis with or without biopsy) while limited autopsy was performed in 16 (17.6%) of cases. Genetic analysis was available in 81/91 (95.6%) cases and chromosome analysis was available in 12/91 (13.2%). There was a slightly increased ratio of males to females (1.33:1). Of the 91 cases, 49.5% were stillbirths. Mean gestational age at termination was 26.1 wks (range 15-37). Thanatophoric dysplasia type 1 accounted for 17/91(18.7%) and osteogenesis imperfecta type 2 accounted for 15/91(16.5%). 

Five percent of all fetal autopsies at a single tertiary referral centre have an underlying skeletal disorder. The most common disorders were Thanatophoric Dysplasia Type 1 (17/91, 18.7%) and Osteogenesis Imperfecta Type 2 (15/91, 16.5%). A combination of radiographic features, gross morphology, histopathology and genetics are required in order to diagnose these rare skeletal dysplasias.

Familiarity with imaging findings, the distribution and lethality of various fetal skeletal dysplasias is crucial in order to provide appropriate counselling for both current and future pregnancies.

Mohan, U, Glanc, P, Keating, S, Chitayat, D, Toi, A, Chong, K, Tomlinson, G, Distribution of Fetal Skeletal Dysplasias in a Tertiary Care Centre: Pathologic and Radiological Findings in 91 Cases.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11011123.html