The clinical picture is variable and manifests into two forms. Patients with lobster claw type lack the third digit [4], which is replaced by a cleft. Additionally, the fingers on either side are typically webbed together. Both hands are involved and the feet are frequently affected.

The second variant is characterized by monodactyly as only the fifth finger is present [7]. There is also a type that includes sensorineural deafness [8].

Syndromic cases exhibit a cluster of manifestations that may include cleft lip/palate, ectodermal dysplasia, and other ectodermal defects due to genetic rearrangement.

• Retinal Pigmentation

  EEM syndrome differs from other ectrodactly syndromes by the characteristic findings in the ocular fundus showing extensive retinochoroidal atrophy with diffuse retinal pigmentation and mild arteriolar attenuation at the posterior pole. [ncbi.nlm.nih.gov]

The clinical assessment consists of the history, physical exam, and the appropriate studies if needed. The features are present at birth and therefore the deformity is apparent. Due to the overlap with other conditions, the newborn will be examined thoroughly to determine if there are other congenital anomalies present.

Prenatal diagnosis

The use of ultrasonography for a survey of the fetal anatomy [9] can detect the abnormality. Additionally, prenatal tests such as amniocentesis and chorionic villus sampling (CVS) will confirm the diagnosis.

Imaging

Radiography will reveal details about missing bones, tendons, and other structures.

Other

Syndromic forms will require additional testing such as skin biopsy.

• Lymphopenia

  He was noted to have T cell receptor excision circle (TREC) analysis below the cutoff for normal on newborn screening and T cell lymphopenia on further immunologic evaluation. [ncbi.nlm.nih.gov]

Patients with ectrodactyly should be managed by a team of pediatricians, orthopedic and plastic surgeons, as well as other professionals. Treatment is individualized based on the specific physical features and disabilities. Surgical correction of the deformity is commonly performed [10] to improve function and appearance. Surgeons aim to close the cleft and rearrange the bones, skin, and tissues. The repair may require subsequent reconstructive procedures.

Other

Early physical and occupational therapy will benefit the child. Also, the use of prosthetics may be helpful.

When ectrodactyly is an isolated condition, it does not impact the patient's life expectancy but it does pose physical challenges. The syndromic form may present certain difficulties depending on associated anomalies, but the prognosis is overall good.

The condition is transmitted in an autosomal dominant pattern [3] although autosomal recessive, sex-linked, and sporadic mutations have been observed. The genetic abnormalities involve a specific region containing homeobox genes DLX5 and DLX6, which are developmental regulatory genes located on chromosome 7 [4].

The prevalence of ectrodactyly is approximately 1 in 8,500 to 1 in 25,000 newborns [5].

Limb development occurs during the 4th week through the 8th week of the gestational period [6]. Through the extensive paddle, plate, and rotational stages, limbs form and grow. Future hands and feet emerge from plates on limb buds while digital rays represent future finger and toes. Normally, cells between rays will undergo apoptosis to free the digits. In the absence of this function, the digits will not separate and hence ectrodactyly presents.

This condition cannot be prevented however genetic counseling is offered to patients and family members.

Ectrodactyly is a rare congenital abnormality of the limb, which is characterized by the absence of the intermediate finger and the presence of a hand cleft. The deformity resembles a lobster claw [1] [2]. Ectrodactyly can develop as part of a syndrome or in isolation. The diagnosis is achieved based on the physical features and history. This condition can also be detected prenatally with the widespread use of ultrasonography. Treatment may include reconstructive surgery and physical /occupational therapy.

Ectrodactyly is a condition in which the hands and feet are not properly developed as there is usually a missing third finger and cleft in the hand, which looks like a lobster claw. This condition may be inherited from an affected parent. The diagnosis is apparent in a newborn due to obvious deformity. The doctor will perform a complete exam to determine if other abnormalities are present. The treatment is usually surgery to correct the appearance and improve the function. Physical and occupational therapy is important as well.

1. Arbués J, Galindo A, Puente JM, et al. Typical isolated ectrodactyly of hands and feet: Early antenatal diagnosis. Journal of Maternal-Fetal and Neonatal Medicine. 2005; 17(4):299–301.
2. Temtamy SA, McKusick VA. The Genetics of Hand Malformations. New York. Alan R. Liss (pub.) 1978.
3. Pascal HG. Pathogenesis of split-hand/split-foot malformation. Human Molecular Genetics. 2003; 12(1):R51–R60.
4. Wieland I, Muschke P, Jakubiczka S, Volleth M, Freigang B, Wieacker P. Refinement of the deletion in 7q21.3 associated with split hand/foot malformation type 1 and Mondini dysplasia. Journal of Medical Genetics. 2004;41(5):e54.
5. Gurrieri F, Everman DB. Clinical, genetic, and molecular aspects of split-hand/foot malformation: an update. American Journal of Medical Genetics A. 2013;161A(11):2860–2872.
6. Duijf P, van Bokhoven H, Brunner HG. Pathogenesis of
   split-hand/split-foot malformation. Human Molecular Genetics. 2003; 12(suppl 1):R51–R60.
7. Bujdoso G, Lenz W. Monodactylous splithand-splitfoot: a malformation occurring in three distinct genetic types. Europopean Journal of Pediatrics. 1980; 133(3):207-215.
8. Haberlandt E, Loffler J, Hirst-Stadlmann A, et al. Split hand/split foot malformation associated with sensorineural deafness, inner and middle ear malformation, hypodontia, congenital vertical talus, and deletion of eight microsatellite markers in 7q21.1-q21.3. Journal of Medical Genetics. 2001;38(6):405-409.
9. Pinette M, Garcia L, Wax JR, et al. Familial ectrodactyly. Journal of Ultrasound in Medicine. 2006; 25(11):1465–7.
10. Kay SP, McCombe D. Central hand deficiencies. In: Green, David P, Hotchkiss, et al. Green's Operative Hand Surgery (5th ed.). Philadelphia: Elsevier/ Churchill Livingstone. 2005; pp. 1404–15.