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Genetic study of scaphocephaly
E Lajeunie1, M Le Merrer, C Bonaïti-Pellie
1U393 INSERM, Hôpital Necker Enfants-Malades, Paris, France.
Insights
Sagittal synostosis, a common skull deformity, affects 1 in 5,000 children. This study suggests it
Area of Science:
- Medical Genetics
- Pediatric Surgery
- Developmental Biology
Background:
- Craniosynostosis involves premature fusion of skull sutures.
- Non-syndromal isolated sagittal synostosis is the most common form.
- Understanding its etiology is crucial for diagnosis and treatment.
Purpose of the Study:
- To investigate the prevalence and inheritance patterns of non-syndromal isolated sagittal synostosis.
- To explore potential etiological factors, including genetic and mechanical influences.
- To analyze familial aggregation and transmission modes.
Main Methods:
- Analysis of 561 probands with non-syndromal isolated sagittal synostosis from a cohort of 1,408 craniosynostosis patients.
- Family history and pedigree analysis for 366 families.
- Segregation analysis of 253 families to determine inheritance patterns.
Main Results:
- Estimated prevalence of sagittal synostosis at 1 in 5,000 children.
- Male predominance (3.5:1 ratio) and no significant maternal or paternal age effect.
- Familial aggregation observed in 6% of cases, suggesting dominant inheritance with 38% penetrance.
- Sporadic cases accounted for 72% of the total.
- Twinning frequency was 4.8%, with one case of concordance in monozygotic twins.
Conclusions:
- Sagittal synostosis likely follows an autosomal dominant inheritance pattern with reduced penetrance.
- A significant proportion of cases are sporadic, prompting consideration of mechanical pathogenesis.
- Further research is needed to elucidate the complex etiology of this common condition.
Abstract:
From a series of 1,408 patients with craniosynostosis hospitalized between 1976 and 1994, 561 probands with non-syndromal isolated sagittal synostosis were analyzed. The prevalence of sagittal synostosis was estimated in the order of 1 in 5,000 children. Family information was obtained from 373 probands distributed among 366 families. The male:female ratio was 3.5:1. There was no maternal or paternal age effect. In 22 of the 366 pedigrees, a high degree of familial aggregation was observed, giving a 6% figure of familial cases. Segregation analysis of 253 families indicates that sagittal synostosis is transmitted as a dominant disorder with 38% penetrance and 72% of sporadic cases. The frequency of twinning was 4.8% with only 1 concordance for sagittal synostosis in a monozygotic twin pair. The possibility of a mechanical pathogenesis in sporadic cases is discussed.