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Perinatally lethal short rib-polydactyly syndromes. 1. Variability in known syndromes
D Sillence1, K Kozlowski, J Bar-ziv
1Medical Genetics Unit, Royal Alexandra Hospital for Children, Camperdown, New South Wales, Australia.
Pediatric Radiology
|January 1, 1987
Summary
Short rib-polydactyly (SRP) syndromes exhibit distinct sex distributions. SRP type III predominantly affects males, while SRP type I shows a higher frequency of females and sex-reversed males, suggesting variable expressivity.
Area of Science:
- Medical Genetics
- Skeletal Dysplasias
- Perinatal Medicine
Background:
- Short rib-polydactyly (SRP) is a group of lethal skeletal dysplasias.
- Previous studies suggested varying epidemiological patterns among SRP subtypes.
- Understanding these patterns is crucial for genetic counseling and diagnosis.
Purpose of the Study:
- To analyze the sex distribution in newborns with lethal short rib-polydactyly (SRP).
- To compare epidemiological findings across different SRP subtypes.
- To explore potential hypotheses for observed sex-based phenotypic variations.
Main Methods:
- Retrospective review of 13 newborns diagnosed with lethal SRP.
- Classification of cases into SRP type II (Majewski) and SRP type III (Verma-Naumoff).
- Analysis of phenotypic features, including sex and presence of major anomalies.
Main Results:
- Eleven cases of SRP type III and two cases of SRP type II were identified.
- A significant excess of males was observed in SRP type III, confirming prior findings.
- SRP type I cases exhibited a high frequency of phenotypic females and sex-reversed males, contrasting with SRP type III.
Conclusions:
- SRP type III demonstrates a male predominance.
- SRP type I presents a contrasting pattern with a higher prevalence of females and sex-reversed males.
- Variable expressivity, particularly in non-Majewski SRP syndromes, may account for these sex-based differences, with affected females showing more severe phenotypes.