ECTRODACTYLY (CLEFT HAND / FOOT)

Ectrodactyly is characterized by the absence of digits (ranging from absence of a single finger, the split hand deformity or absence of all but the fifth digit). The classical appearance is the absence of the third digit with clefting into the proximal portion of the hand and syndactyly of the remaining digits on each side of the cleft. The hand / foot has the appearance of a lobster claw.

Cleft hand / foot is therefore also referred to as ectrodactyly, lobster claw hand / foot or split hand / foot. It is characterized by the absence of the central digit rays with splitting of the hand / foot into radial and ulnar segments. This anomaly results from abnormal development of the hand / and or foot plates during the seventh week of gestation.

CLASSIFICATION

Two subgroups are described:

• Typical type characterized by absence of one or several median digits or rays in the presence of normal rays bordering the cleft. The absence of both the finger and metacarpal results in a deep V-shaped cleft that divides the hand into ulnar and radial parts.
• Atypical type in which the remaining rays are also affected by various reduction anomalies. There is a much wider cleft formed by a defect of the metacarpals and middle fingers. A wide U-shaped cleft with only a thumb and small finger remain.

INHERITANCE

• Sporadic.
• Autosomal dominant trait.
• Isolated anomaly is caused by an alteration in chromosome 7 (7q21) (SHFM !); 10 (10q24) (SHFM 3); 0r 3 (3q27) (SHFM 4) (4-6).
• A Pakastani kindred in which 36 members in 7 generations have demonstrated an X-linked form )Xq26) (SHFM 2) (7).

ULTRASOUND

Link to Ultrasound

ASSOCIATED ANOMALIES

• Ectrodactyly-ectodermal dysplasia-cleft lip/palate (EEC) syndrome.
• Ectodermal dysplasia (anomalies of hair, teeth, nails, lacrimal duct and sweat glands, dry skin and sparse hair).
• Slit hand and foot.
• Cleft lip or palate (usually bilateral).
• Anodontia.

Claw hand – 2^nd and 3^rd difits missing
Cleft Lip

• Walker-Clodius syndrome.
• Cornelia de Lange syndrome.
• Arthrogryposis multiplex congenita.
• Tibial Aplasia-Ectrodactyly Syndrome.
• Karsch-Neugebauer syndrome (split foot / hand with congenital nystagmus).
• Acro-renal syndrome.
• Fontaine syndrome.
• LA Ronge syndrome.

DIFFERENTIAL DIAGNOSIS

· Brachydactyly.

· Multiple synostosis syndrome.

· Amniotic band syndrome

· Ectridactyly-ectodermal dysplasia – cleft lip/palate syndrome.

· Ectrodactyly and triphalangeal thumb.

· Ectrodactyly with central polydactyly.

· Acrorenal syndrome with mandibulofacial dysostosis.

· Ectrodactyly with congenital nystagmus.

· Lacrimo-auriculo-dento-digital syndrome (LADD)

· Ectrodactyly with ectodermal dysplasia (EE)

· Acro-dermato-ungual-lacrimal-tooth syndrome (ADULT).

REFERENCES

1. Barsky AJ. Cleft hand: Classification, incidence and treatment. Review of the literature and report on nineteen cases. J Bone Joint Surg (Am) 1964;46:1707-1720.
2. Kohler R, Sousa P, Jorge CS. Prenatal diagnosis of the ectrodactyly, ectodermal dysplasia with cleft palate (EEC) syndrome. J Ultrasound Med 1989;8:337-339.
3. Bronshtein M, Gershoni-Baruch R. Prenatal transvaginal diagnosis of the EEC syndrome. Prenat Diagn 1993;13:519-522.
4. Haratz-Rubenstein N Yeh M –N Timor Trisch IE et.al. Prenatal diagnosis of split hand anomaly: how early is early. Ultrasound Obstet Gynecol 1996;8:57-61.
5. Birch-Jensen A. Congenital deformities of the upper extremities. Copenhagen: Ejnar Munksgaard, 1994.
6. Cobben J, Verheij JM, Robinson PH et.al. Bilateral split hand / foot malormation and inv (7) (p22q21.3). J Med Genet 1995;32:375-378.
7. Palmer SE, Scherer SW, Kukolich M et.al. Evidence for locus heterogenicity in human autosomal dominant split hand-foot malformation. Am J Hum Genet 1994;55:21-26.