Mermaid syndrome associated with VACTERL-H syndrome

Area of Science:

• Medical Genetics
• Developmental Biology
• Teratology

Background:

• Sirenomelia, or mermaid syndrome, is a rare congenital anomaly affecting approximately 1.5-4.2 per million pregnancies.
• The co-occurrence of sirenomelia with VACTERL-H syndrome is exceptionally rare, with only two prior documented cases.
• Understanding the genetic and developmental underpinnings of these conditions is crucial for diagnosis and management.

Observation:

• A 15-year-old patient presented with progressive abortion during her first pregnancy.
• Prenatal imaging revealed a malformed fetus, including hydrocephalus and spinal defects.
• Fetopathological examination confirmed Type I sirenomelia associated with multiple VACTERL-H syndrome anomalies.

Findings:

• The case presented Type I sirenomelia alongside myelomeningocele, hydrocephalus, anal imperforation, single umbilical artery, renal and bladder agenesis, tracheo-esophageal fistula, and genital agenesis.
• This constellation of defects aligns with VACTERL-H syndrome, highlighting a significant overlap.
• The patient's low socioeconomic status and avoidance of folic acid supplementation were noted, though causality remains to be established.

Implications:

• This case supports the hypothesis that sirenomelia and VACTERL-H syndrome may represent variable expressions of a singular pathological process.
• Disruptions in blastogenesis at different embryonic stages could lead to these distinct yet related malformation syndromes.
• Further research into early embryonic development is warranted to elucidate the shared etiology of these rare conditions.