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Related Experiment Video

Updated: May 8, 2026

In Vivo Modeling of the Morbid Human Genome using Danio rerio

In Vivo Modeling of the Morbid Human Genome using Danio rerio

Published on: August 24, 2013

Sirenomelia apus: a rare deformity.

Vinayak Y Kshirsagar¹, Minhajuddin Ahmed, Sylvia M Colaco

¹Department of Pediatrics, Krishna Institute of Medical Sciences University, Karad, Maharashtra, India.

Journal of Clinical Neonatology

|September 13, 2013

Summary

Sirenomelia, or mermaid syndrome, is a rare congenital condition causing lower limb fusion and severe organ issues. It often occurs with twinning and may stem from early embryonic damage.

Keywords:

Caudal regression mermaid syndrome sirenomelia

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Midface Hypoplasia and Cranial Base Morphology in Syndromic Craniosynostosis: A Comparative Analysis Study Using a Predictive Regression Model

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Published on: November 4, 2025

Area of Science:

Developmental biology
Medical genetics
Congenital malformations

Background:

Sirenomelia, a rare congenital malformation, presents with fused lower limbs and is of uncertain etiology.
It is frequently associated with significant urogenital and gastrointestinal anomalies.
Approximately 300 cases are documented, with 15% linked to monozygotic twinning.

Observation:

The defining characteristic is the fusion of the lower extremities.
Associated malformations impact critical organ systems, including the genitourinary and digestive tracts.
A notable association exists with twinning, particularly monozygotic (identical) twins.

Findings:

The etiology of sirenomelia remains largely unknown.
The condition is linked to caudal regression syndrome, suggesting an early gestational insult to the caudal mesoderm.
The high incidence in monozygotic twins points towards potential shared developmental pathways or environmental factors.

Implications:

Understanding sirenomelia's origins is crucial for early diagnosis and potential intervention.
Further research into caudal mesoderm development could elucidate causative factors.
Investigating the link with twinning may offer insights into developmental disruptions.