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Year : 2014  |  Volume : 25  |  Issue : 2  |  Page : 243-247
Lobster claw deformity

1 Department of Orthodontics, IMS, BHU, Uttar Pradesh, India
2 Department of Oral Pathology, IMS, BHU, Uttar Pradesh, India
3 Faculty of Dental Sciences, IMS, BHU, Uttar Pradesh, India
4 Unit of Dentistry, Marwari Hospital, Uttar Pradesh, India
5 Unit of Dentistry, Hindu Seva Sadan Hospital, Varanasi, Uttar Pradesh, India

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Date of Submission05-Apr-2012
Date of Decision21-Jun-2013
Date of Acceptance02-Aug-2013
Date of Web Publication4-Jul-2014


Endogenous erythroid colony (EEC) syndrome comprise of three cardinal features, i.e. ectrodactyly, ectodermal dysplasia and cleft lip. EEC itself has three different forms. Ectrodactyly (absence of one or more digits) can be present with clefting in the proximal portion of hand or foot known as split hand foot malformation (SHFM) or lobster claw deformity. SHFM can be of four types depending upon the different responsible chromosomal loci. SHFM-4 can be present as pure limb malformation (non-syndromic form). In this article, describes a rare case report of lobster claw deformity patient.

Keywords: Ectrodactyly, endogenous erythroid colony syndrome, lobster claw, p63, split hand foot malformation

How to cite this article:
Agrawal A, Agrawal R, Singh R, Agrawal R, Agrawal S. Lobster claw deformity. Indian J Dent Res 2014;25:243-7

How to cite this URL:
Agrawal A, Agrawal R, Singh R, Agrawal R, Agrawal S. Lobster claw deformity. Indian J Dent Res [serial online] 2014 [cited 2022 Oct 7];25:243-7. Available from:
A complex of ectrodactyly, ectodermal dysplasia and cleft lip with or without cleft palate Endogenous erythroid colony (EEC) syndrome is a rare type of congenital anomaly. [1] Any of the three cardinal signs can be present with variable expressions. [1] EEC was first described by Cockayne in 1936, but the acronym was coined by Rudiger et al. in 1970. [1],[2]

Ectrodactyly is the term used to describe a heterogeneous group of hand and foot malformations ranging from the absence of a single finger to the absence of all but the fifth digit. [3] A characteristic from of ectrodactyly is the split hand foot malformation (SHFM) due to the absence of third digit with clefting into the proximal portion of hand and foot and syndactyly of the remaining digits on each side of the cleft, the hand having a characteristic appearance resembling a lobster claw. [3]

Different combinations of ectrodermal dysplaia, orofacial clefting and limb malformations as the key characteristics, are seen in five different syndromes: [4] EEC syndrome (most common, OMIM 604292), ankyloblepharon-ectodermal defect-cleft lip/palate syndrome (AEC, OMIM 106260), Limb mammary syndrome (LMS, OMIM 603543), Acro-dermato-ungual-lacrimal-tooth syndrome (adult, OMIM 103285) and Rapp-hodgkin syndrome (RHS, OMIM 129400). The transcription factor p63 is a key regulator of ectodermal, orofacial and limb development. This became apparent in 1999 by the generation of p63 knockout mice [5],[6] and by the finding of dominant mutations in human disorders with ectodermal dysplasia split hand/foot malformation (SHFM) and orofacial clefting. [4] Furthermore, two non-syndromic disorders are caused by p63 mutations, which are isolated SHFM-4 (OMIM 605289) and non-syndromic cleft lip. [4]

   Case Report Top

A 12-year-old male patient [Figure 1] reported with the chief complaints of decayed teeth and hypersensitivity. Patient was apparently normal 1 month back then he observed the carious teeth in relation to 16, 26, 36, 75 and 46. He has no pain, only sensitivity is present.
Figure 1: Extraoral photograph

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According to the patient and his parents, he did not have any medical problem and was not on any medication. Patient told that this was his first dental visit. Family history revealed that he was born to consanguineous parents and no other family member had similar features. His personal history showed that he takes mixed diet and had a habit of brushing his teeth with neem sticks.

On general examination, it was observed that there was the absence of digits with deep "v" clefts in all four limbs [Figure 2], [Figure 3], [Figure 4]. Hands of the patients showed absence of the index and middle finger. There were three digits present, which were of abnormal shape and size. Feet revealed the absence of the second toe and fusion of 3 rd , 4 th and 5 th toes with a deep cleft between the fused toes and the first toe.
Figure 2: Dorsal view (hand)

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Figure 3: Ventral view (hand)

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Figure 4: Dorsal view (foot)

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Intraoral examination [Figure 5] showed missing upper and lower right central incisors and lower left central incisor (11, 31, 41). Total number of clinical teeth present were 22 (In Federation Dentaire Internationale : 16, 15, 14, 53, 12, 21, 22, 63, 24, 25, 26, 46, 85, 44, 83, 42, 71, 72, 73, 34, 75 and 36). Decayed, missing and filled teeth (DMFT) score was found to be 5. There was class I molar relation. Intraoral soft-tissue appeared to be normal. A provisional diagnosis of Lobster - claw syndrome was established.
Figure 5: Intraoral examination view

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Intraoral periapical radiograph of the upper and lower anterior, orthopantomogram (OPG) [Figure 6], hand and wrist radiograph [Figure 7] and occlusal radiograph [Figure 8] and [Figure 9] were taken for complete intraoral examination. On OPG observation, it is found that 11, 31, 32, 33 and 45 tooth germs were missing. 13, 17, 23, 27, 37, 35 and 47 were found erupting. In hand and wrist radiograph absence of metacarpals and phalanges was found. Based on the clinical features a diagnosis of lobster claw deformity was made.
Figure 6: Orthopantomogram

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Figure 7: Hand and wrist radiograph

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Figure 8: Maxillary occlusal radiograph

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Figure 9: Mandibular occlusal radiograph

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Differential diagnoses including EEC (ectrodactyly ectodermal dysplasia, clefting), orofacial digital syndrome, apert syndrome, chromosomal syndrome were excluded and a final diagnosis of the lobster claw deformity was established. Though the case showed the deformity, there were some findings such as depressed nasal bridge, sparse eyebrows, missing teeth, dry and smooth skin, which are features of ectodermal dysplasia.

Patient counseling was performed along with his parents. Informed consent was taken from parents after discussing the treatment plan. Patient was send to periodontics for oral prophylaxsis. The decayed tooth was restored with glass ionomer cement (3M ESPE Ketac Cem) [Figure 10]. Pit and fissure sealant (3M™ ESPE™ Clinpro™) was applied on posterior teeth having deep fissure and groove. Fluoride was applied as a preventive measure.
Figure 10: Decayed tooth restored with glass ionomer cement

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   Discussion Top

There are three different forms of EEC syndrome: EEC1 (OMIM 129900,Gene map locus - 7q11.2-q21.3), EEC2 and EEC3 (OMIM 604292, Gene map locus - 3q27). EEC3 results from mutation in gene and encoding p63 on chromosome 3q27. It was reported by O'Quinn JR et al. (1996) in a Dutch family that chromosome 19 was linked for occurrence of EEC2, but later van Bokhoven et al. reported that the linkage to chromosome 19 appears to be a fortuous finding. [7],[8]

In earlier studies five frequently mutated amino acids were found, i.e., R204; R227; R279; R280 and R304 in the EEC population. [4] These five mutations explain almost 90% of the EEC syndrome patient. [9],[10] Recent genotype-phenotype analyses for the five hotspot mutation revealed significant differences between the corresponding phenotype; for instance cleft lip/palate is present in the R304 mutation population (80%), whereas R227 patients seldom have cleft lip/palate. Syndactyly is completely absent in R227 population while 30-60% of the other hotspot mutation population have syndactyly. [11]

Genitourinary defects are frequently observed in R227 mutation population (40%), while significantly less in other population. [11] It thus seems that these hotspot mutations exert specific effects. Such specificity might be brought about by different effects of these mutations on promoters for p63 transcriptional target genes. Alternatively, these hotspot mutations may exhibit gain-of-function effects, similar as for the p53 hotspot mutation. [11] In presented case, no such additional findings were present.

EEC syndrome (OMIM No. 129900) is rare and usually inherited in an autosomal dominant manner. The trait is invariable in its penetrance and clinical expressivity. [1]

The term ectrodactyly denotes congenital absence of all or part of one or more fingers or toes. Syndactyly indicates fused or webbed fingers or toes. A permanent deflection of one or more fingers is referred to as clinodactyly. [1]

In addition to three cardinal features of EEC syndrome, other features may also be present with the syndrome such as eye and lacrimal duct anomalies, mid facial hypoplasia, auricular anomalies, short stature, genitourinary anomalies, central nervous system anomalies such as hearing loss and mental retardation and multiple nevi. [1] McNab AA et al. found the congenital absence of the stapes and part of the incus in one of their members of the family whose effected members had a conductive hearing loss in addition to the features of EEC syndrome. [2]

SHFM-4 is a "pure" limb malformation (ectrodactyly and syndactyly) condition, thus without orofacial clefting or ectodermal dysplasia. The non-syndromic SHFM4 is caused by several mutations, which are dispersed throughout the p63 gene: A point mutation in the transactivation domain (R58C), a splice-site mutation in front of exon 4 (3'ss intron 4), four missense mutations in the deoxyribonucleic acid binding domain (DBD) (K193E, K194E, R280C, R280H) and two nonsense mutations in the terminal inhibitory domain (Q634X, E639X). [4] The present case is of pure non-syndromic lobster claw deformity.

Four loci for split hand-split foot malformation (SHFM) have been mapped: [12],[13]

  1. SHFM1 on chromosome 7q21,
  2. SHFM2 on chromosome Xq26,
  3. SHFM3 on chromosome 10q24 and
  4. SHFM4 recently found to be caused by mutations in the p63 gene, a homologue of the archetypal tumor suppressor TP53, on chromosome 3q27.

The transcription factor p63 is a key regulator of ectodermal, orofacial and limb development. Ectodermal dysplasia is one of the three main characteristic of the associated syndromes. [4] The number of teeth is often less than in healthy individuals, indicating that there is a reduced number of teeth placodes in p63 associated syndromes. The teeth can also be malformed by a conical shape and poor enamel formation, causing subsequent tooth decay. [4]

SHFM-4 constitutes the second part of the p63 syndrome phenotype. Hands and feet are often malformed and have a severe median cleft in the palm and/or in the sole. These clefts usually occur in conjugation with ectrodactyly. Fusion of fingers or toes, which is called syndactyly can be seen in conjugation with ectrodactyly. In most cases, SHFM-4 is part of syndrome, but it can also be present in isolation, without other symptoms. EEC syndrome is mainly caused by point mutation in the DBD of the p63 gene. [4]

Detailed examination of fetal hand and feet is an important component of ultrasonographic evaluation of fetuses with congenital abnormalities and of those at risk of chromosomal abnormalities. [3] This routine has been increasingly incorporated into detail second trimester ultrasonographic examination. However, there are few reports in the literature reporting the prenatal detection of hand malformations, most of them in fetuses with chromosomal abnormalities or in association with multiple congenital anomalies. [3] Prenatal diagnosis of ectrodactyly has previously been reported in fetuses either with a familial history of ectrodactyly or in association with the EEC syndrome. Examination of fetal hands and feet during routine detailed second trimester ultrasonography should make the detection of anomalies of the extremities more common. In high risk pregnancies, transvaginal ultrasonography may facilitate an early second trimester recognition of hand abnormalities, especially because of fetal figure at this stage are usually extended and separated from each other. [3]

Management of cases with EEC syndrome requires a multidisciplinary approach that include a Dermatologist, plastic surgeon, Ophthalmologist and if needed, a speech therapist. Most patients need no surgical intervention as there is no functional problem except for the cosmetic disturbance. [1]

   References Top

1.Cyriac MJ, Lashpa E. Lobster-claw hand: A manifestation of EEC syndrome. Indian J Dermatol Venereol Leprol 2006;72:54-6.  Back to cited text no. 1
[PUBMED]  Medknow Journal  
2.McNab AA, Potts MJ, Welham RA. The EEC syndrome and its ocular manifestations. Br J Ophthalmol 1989;73:261-4.  Back to cited text no. 2
3.Leung KY, MacLachlan NA, Sepulveda W. Prenatal diagnosis of ectrodactyly: The 'lobster claw' anomaly. Ultrasound Obstet Gynecol 1995;6:443-6.  Back to cited text no. 3
4.Leoyklang P, Siriwan P, Shotelersuk V. A mutation of the p63 gene in non-syndromic cleft lip. J Med Genet 2006;43:e28.  Back to cited text no. 4
5.Yang A, Schweitzer R, Sun D, Kaghad M, Walker N, Bronson RT, et al. P63 is essential for regenerative proliferation in limb, craniofacial and epithelial development. Nature 1999;398:714-8.  Back to cited text no. 5
6.Mills AA, Zheng B, Wang XJ, Vogel H, Roop DR, Bradley A. p63 is a p53 homologue required for limb and epidermal morphogenesis. Nature 1999;398:708-13.  Back to cited text no. 6
7.O'Quinn JR, Hennekam RC, Jorde LB, Bamshad M. Syndromic ectrodactyly with severe limb, ectodermal, urogenital, and palatal defects maps to chromosome 19. Am J Hum Genet 1998;62:130-5.  Back to cited text no. 7
8.van Bokhoven H, Hamel BC, Bamshad M, Sangiorgi E, Gurrieri F, Duijf PH, et al. p63 Gene mutations in EEC syndrome, limb-mammary syndrome, and isolated split hand-split foot malformation suggest a genotype-phenotype correlation. Am J Hum Genet 2001;69:481-92.  Back to cited text no. 8
9.Rinne T, Hamel B, van Bokhoven H, Brunner HG. Pattern of p63 mutations and their phenotypes - Update. Am J Med Genet A 2006;140:1396-406.  Back to cited text no. 9
10.van Bokhoven H, Brunner HG. Splitting p63. Am J Hum Genet 2002;71:1-13.  Back to cited text no. 10
11.Koonin EV, Rogozin IB, Glazko GV. P53 gain-of-function: Tumor biology and bioinformatics come together. Cell Cycle 2005;4:686-8.  Back to cited text no. 11
12.Elke Sleurs, Luc De Catte, George E. Tiller. Split hand split foot syndrome, [Last accessed on 2001].  Back to cited text no. 12
13.Ianakiev P, Kilpatrick MW, Toudjarska I, Basel D, Beighton P, Tsipouras P. Split-hand/split-foot malformation is caused by mutations in the p63 gene on 3q27. Am J Hum Genet 2000;67:59-66.  Back to cited text no. 13

Correspondence Address:
Rahul Agrawal
Department of Oral Pathology, IMS, BHU, Uttar Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0970-9290.135935

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  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10]

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