A case of atypical cleft hand - reported with ontogenetic review

Abstract

An asymptomatic atypical U shaped cleft hand has been found in a 21-year-old lady attending OPD. On digital skiagram it was found that central digits were absent with remnants of bases of the metacarpals, which have fused with the carpal bones. Moreover, the scaphoid and trapezium had fused to form a single mass. There was no other anomaly in other limbs, so far searched for. An endeavor has been made to explain the anomaly with ontogenetic review.

Keywords: Apical ectodermal ridge; Early differentiation model; Homeobox (Hox) gene; Lobster-claw hand; Progressive zone model.

[Table/Fig-1]:

The figure showing two hands of the lady: right hand having atypical spreaded-U clefting in hand, with normal fellow hand

[Table/Fig-2]:

Besides the one limb, there were no obvious anomalies in other limbs to the lady (hence a monomelia)

[Table/Fig-3]:

Skiagram of the affected hand, showing (1. Schapho-trapezo-metacarpal fusion in first digit( 2. Normal trapezoid and capitate with fused bases of the respective metacarpals. (3. Separate rudimentary base of the third metacarpal (4. Isolated prominent fifth metacarpal (5. Proximal phalanx of little finger

[Table/Fig-4]:

Skiagram of both hands, where the left side is normally developed

[Table/Fig-5]:

Developmental nomenclature of different parts of a developing limb. ‘Stylopod’ demarcates the arm, ‘Zeugopod’ demarcates the forearm and ‘Autopod’ demarcates the hand

[Table/Fig-6]:

Above figure represents two ‘models’ of development of the limb. After the AER (Apical Ectodermal ridge) appears in the side of the flank, there are two hypotheses of limb growth. [In figure abbreviated as, AER: Apical Ectodermal ridge; PZ: Progress zone; ZPA: Zone of Polarising activity; S: Stylopod formative genes; Z: Zeugopod formative genes; A: Autopod formative genes]

[Table/Fig-7]:

Figure describes the gradual expression of Hox genes along with the growth of the extremity. [In figure abbreviated as, Shh: Sonic hedgehog gene; AER: Apical Ectodermal ridge; d 9-13: expression of Hox D 9-13 genes]

[Table/Fig-8]:

sequential Hox gene expression in formation of different components of the developing limb