ARACHNODACTYLY

Arachnodactyly refers to long spider-like digits.

ULTRASOUND

• Long digits.
• Middle finger/total hand length ratio is normally 0.43 in the newborn.

ASSOCIATED SYNDROMES

• Marfans syndrome.
• Homocystinuria.
• Congenital contractural arachnodactyly (CCA) or Beals-Hecht syndrome (1-17) is an autosomal dominant disorder caused by mutations in the fibrillin-2 (FBN2) gene ), which is located on chromosome 5q23-31. The principal features of CCA are a marfanoid habitus, multiple congenital contractures, camptodactyly, arachnodactyly, kyphoscoliosis, muscular hypoplasia, and external ear malformations.
• marfanoid habitus
• multiple congenital contractures,
• camptodactyly (78%), arachnodactyly, club feet (28%)
• kyphoscoliosis,
• muscular hypoplasia,
• malformations of the external ears ('crumpled ears')
• cardiac abnormalities(15%) including mitral valve prolapse, atrial septal defect, ventricular septal defect, type B interrupted aortic arch, and aortic hypoplasia
• In most cases of CCA life expectancy is normal (a few reported cases of lethal CCA due to complex cardiac abnormalities or generalized muscular atrophy).

DIFFERENTIAL DIAGNOSIS (1-17)

	Congenital contractural arachnodactyly	Marfan syndrome	Achard syndrome	Homocystinuria	Distal arthrogryposis
Inheritance	Autosomal Dominant	Autosomal dominant	Autosomal dominant	Autosomal recessive	Autosomal Dominant, X-linked
Skeleton	Dolichostenomelia, Kyphoscoliosis	Dolichostenomelia (more frequent and severe than in CCA) Scoliosis Thoracic lordosis	No dolichostenomelia	Dolichostenomelia, Osteoporosis
Joints	Congenital and symmetrical joint contractures -of large and small joints (maximally involve the knees) -no joint laxity or rigidity-spontaneous resolution with time	No congenital joint contractures, contractures may develop during childhood (especially of elbows, hands and feet) -joint laxity-progressive	No joint contractures, joint laxity limited to hands and feet	Contractures not common, deformities develop after birth	Multiple, congenital joint contractures -proximal joints marked -internal rotation of the upper extremities-external rotation of the lower extremities-rigidity
Skull	Oval skull	Dolichocephaly	Broad skull brachycephaly
Eyes	No significant ocular problems	Eye abnormalities in 80% -ectopia lentis, severe myopia, retinal detachment, glaucoma -lead to severe limitation of visual acuity or total blindness	No ocular defects	Ectopia lentis
Ears	Crumpled, 'cabbage leaf like' ears		No ear abnormalities
Hands	Arachnodactyly	Arachnodactyly (more frequent and severe than in CCA)	Arachnodactyly	Arachnodactyly	No arachnodactyly
Cardiovascular system	Usually cardiovascular system not affected, congenital heart defects in 15%-mitral valve prolapse, atrial septal defect, ventricular septal defect, aortic hypoplasia	Cardiovascular complications in 2/3aortic aneurysm and regurgitation, lesions of pulmonary artery and mitral valve with mitral insufficiency, arrhythmias	No cardiac defects
Other	No mental retardation	No mental retardation, spinal arachnoid cysts		Thromboembolism, mental retardation
Adapted from: Kölble, N., Wisser, J., Babcock, D., Maslen, C., Huch, R. & Steinmann, B. Prenatal ultrasound findings in a fetus with congenital contractural arachnodactyly. Ultrasound in Obstetrics & Gynecology  20 (4), 395-399

REFERENCES

1. Lee B, Godfrey M, Vitale E, Hori H, Mattei MG, Sarfarazi M, Tsipouras P, Ramirez F, Hollister DW. Linkage of Marfan syndrome and a phenotypically related disorder to two different fibrillin genes. Nature 1991; 352: 330-334
2. Tsipouras P, Del Mastro R, Sarfarazi M, Lee B, Vitale E, Child AH, Godfrey M, Devereux RB, Hewett D, Steinmann B, Viljoen D, Sykes BC, Kilpatrick M, Ramirez F. Genetic linkage of the Marfan syndrome, ectopia lentis, and congenital contractural arachnodactyly to the fibrillin genes on chromosomes 15 and 5. The International Marfan Syndrome Collaborative Study. N Engl J Med 1992; 326: 905-909
3. Beals RK, Hecht F. Congenital contractural arachnodactyly. A heritable disorder of connective tissue. J Bone Joint Surg Am 1971; 53: 987-993
4. Hecht F, Beals RK. 'New' syndrome of congenital contractural arachnodactyly originally described by Marfan in 1896. Pediatrics 1972; 49: 574-579
5. Ramos Arroyo MA, Weaver DD, Beals RK. Congenital contractural arachnodactyly. Report of four additional families and review of literature. Clin Genet 1985; 27: 570-581
6. McKusick VA. Mendelian Inheritance in Man: Catalogs of Autosomal Dominant, Autosomal Recessive, and X-linked Phenotypes, 12th edn. Baltimore and London: Johns Hopkins University Press 1998
7. Anderson RA, Koch S, Camerini Otero RD. Cardiovascular findings in congenital contractural arachnodactyly: report of an affected kindred. Am J Med Genet 1984; 18: 265-271
8. Wang M, Clericuzio CL, Godfrey M. Familial occurrence of typical and severe lethal congenital contractural arachnodactyly caused by missplicing of exon 34 of fibrillin-2. Am J Hum Genet 1996; 59: 1027-1034
9. Maslen C, Babcock D, Raghunath M, Steinmann B. A rare branch-point mutation is associated with missplicing of fibrillin-2 in a large family with congenital contractural arachnodactyly. Am J Hum Genet 1997; 60: 1389-1398
10. PA, Putman EA, Carmical SG, Kaitila I, Steinmann B, Child A, Danesino C, Metcalfe K, Berry SA, Chen E, Vincent Delorme V, Thong M-K, Adès LC, Milewicz DM. FBN2 mutations in congenital contractural arachnodactyly: delineation of the molecular pathogenesis and clinical phenotype. Hum Mutation 2002; 19: 39-48
11. Viljoen D. Congenital contractural arachnodactyly (Beals syndrome). J Med Genet 1994; 31: 640-643
12. Courtens W, Tjalma W, Messiaen L, Vamos E, Martin JJ, Van Bogaert E, Keersmaekers G, Meulyzer P, Wauters J. Prenatal diagnosis of a constitutional interstitial deletion of chromosome 5 (q15q31.1) presenting with features of congenital contractural arachnodactyly. Am J Med Genet 1998; 77: 188-197
13. Ramirez F. Fibrillin mutations in Marfan syndrome and related phenotypes. Curr Opin Genet Dev 1996; 6: 309-315
14. Belleh S, Spooner L, Allanson J, Godfrey M. Prenatal diagnosis in congenital contractural arachnodactyly. Genet Test 1997; 1: 293-296
15. Currarino G, Friedman JM. A severe form of congenital contractural arachnodactyly in two newborn infants. Am J Med Genet 1986; 25: 763-773
16. Lipson EH, Viseskul C, Herrmann J. The clinical spectrum of congenital contractural arachnodactyly. A case with congenital heart disease. Z Kinderheilkd 1974; 118: 1-8
17. Macnab AJ, D'Orsogna L, Cole DE, Baguley PE, Adderley RJ, Patterson MW. Cardiac anomalies complicating congenital contractural arachnodactyly. Arch Dis Child 1991; 66 (10: Spec No): 1143-1146