Figure 11: One of the rockerbottom feet.
Craniosynostosis syndromes have been variously described with acronyms and a definitive classification remains controversial. Apert syndrome (Acrocephalosyndactyly, Type I), Apert-Crouzon syndrome (Acrocephalosyndactyly, Type II), Saethre-Chotzen syndrome (Acrocephalosyndactyly, Type III), and Pfeiffer syndrome (Acrocephalosyndactyly, Type V) categories have been reported. Craniosynostosis syndromes with polysyndactyly have also been reported. Noack syndrome (Acrocephalopolysyndactyly, Type I) which is now generally accepted as a variant of Acrocephalosyndactyly, Type V, Carpenter syndrome (Acrocephalopolysyndactyly, Type II), Sakati-Nyhan syndrome (Acrocephalopolysyndactyly, Type III) and Goodman syndrome (Acrocephalopolysynda- ctyly, Type IV) variants have been described, and Grieg cephalopolysyndactyly syndrome is another related entity that may actually represent a spectrum of phenotypic expression. There is a wide variability in phenotypic expression which has led to the inherent difficulties in nosology that is apparent in the literature.
Inheritance patterns for acrocephalosyndactyly and acrocephalopolysyndactyly are both autosomal dominant and autosomal recessive. However, the majority of cases occur sporadically, with most representing spontaneous mutations in families having no history of congenital aberrations. There appears to be an increased risk related to advanced parental age1. Variability in phenotypic expression is well documented in the literature4,8,9. The prevalence of craniosynostosis with or without additional anomalies has been estimated at approximately 3.43:10,000 by Lammer et al.10.
The etiology for these disorders is unknown; however, an abnormality in mesenchymal differentiation has been proposed12. Furthermore, craniosynostosis may be better understood as an abnormality with various causes rather than an etiologic entity11. Chromosome analyses are usually normal in these patients; however, a translocation13 has been reported. Spontaneous mutations account for the vast majority of cases1.
The primary skeletal malformations exhibited by this fetus suggest a diagnosis that falls within the broad spectrum of craniosynostosis syndromes. Frequent overlap in clinical features and extreme variability among individuals in manifestations complicates definitive categorization. Classification schemes are constantly being revised as continued descriptions allow specific syndromes to be recognized as variants or subgroups of others.
The collective dysmorphic features identified in this fetus most likely represent a variant of one of the dyscraniophalangeal syndromes described above. However, syndactyly was not a prominent feature, and the limb malformations appeared more consistent with the acrocephalopolysyndactyly syndromes. The postaxial hexadactyly (pedunculated postminimi) present in the hands as well as agenesis of the corpus callosum has been described in association with Greig cephalopolysyndactyly14. Lumbar meningocele, imperforate anus, and "rockerbottom" feet were features present in this fetus that defy the current classification system and may represent fortuitous associations.
1 Risch N, Reich EW, et al.: Spontaneous mutation and parental age in humans. Am J Hum Genet 41:218-248, 1987.
2. Taravath S and Tonsgard JH: Cerebral malformations in Carpenter syndrome. Pediatr Neurol 9:230-4, 1993.
3. Patton MA, Goodship J, Hayward R, et al.: Intellectual development in Aperts syndrome: A long- term follow up of 29 patients. Medical Genetics 25:164-167, 1988.
4. Gershoni-Baruch R: Carpenter syndrome: Marked variability of expression to include the Summitt and Goodman syndromes. Am J Med Genet 35:236-240, 1990.
5. Kaplan, LC: Clinical assessment and multispecialty management of Apert syndrome. Clin Plast Surg 18 No 2, 1991.
6. Lefebvre A, Travis F, et al.: A psychiatric profile before and after reconstructive surgery in children with Aperts syndrome. Br J Plast Surg 39:510-513, 1986.
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8. Niemann-Seyde SC, Eber SW, Zoll B. Saethre-Chotzen syndrome (ACS III) in four generations. Clin Genet 40:271-276, 1991.
9. Cohen, MM, Kreiborg S: Genetic and family study of the Apert syndrome. J Craniofac Genet Dev Biol 11:7-17, 1991.
10. Lammer EJ, Cordero JF, Wilson MJ, et al.: Investigation of a supspected increased prevalence of craniosynostosis -Colorado, 1978-1982 Proc Greenwood Genet. Ctr. 6, 126-127; Document EPI-83-56-2, Public Health Service-CDC-Atlanta 4/8/87;p.7.