View source for Talk:Paper - An unusual form of brachyphalangy and syndactyly with double proximal phalanx in the middle fingers (1932)

AN UNUSUAL FORM OF BRACHYPHALANGY AND
SYNDACTYLY, WITH DOUBLE PROXIMAL PHALANX
IN THE MIDDLE FINGERS

By E. A. COCKAYNE, D.M., F.R.C.P.

R.J., the boy with the abnormality, was brought to the Hospital for Sick
Children, Great Ormond Street, in October, 1931. He was then aged 8 months,
the only child of first cousins, who are English and live at Watford. His mother
says that as far as she knows no similar deformity has been present in any other
member of the family. The boy appears to be of normal intelligence, but is
small for his age, weighing 10 lb. 5 oz. at 18 months, and has a harsh systolic .
murmur, which is loudest over the lower part of the sternum and is probably
due to a patent interventricular septum.

In each hand the index finger is very short and sharply bent in the middle
so that the distal end points towards the middle finger. There is complete
syndactyly of the middle and ring fingers of each hand, but the union is confined to the soft tissues and the nails are not joined together, and each middle
finger is reduced in length so that it is shorter than the ring finger. A skiagram
taken in October shows that in both index fingers the middle phalanx is represented by.a minute spherical bone, and the proximal phalanx is very small,
misshapen, and much shortened in the right hand and shortened to a less
extent in the left. In the middle finger of the right hand the proximal phalanx
is represented by five small bones, of which three lie in the long axis of the
finger on its radial side, the middle one being considerably the largest, and the
other two lie close together at the same level on its ulnar side. In the left hand
the proximal phalanx of the middle finger is represented by two small bones,
one of which lies on its radial side in the same position as the three bones in the
middle finger of the opposite hand, and the other lies on its ulnar side. These
bones are all very small, and even combined their mass would be much less
than that of a normal proximal phalanx. The proximal phalanx of the left ring
finger is considerably shorter than that of the right one, which appears to be
of normal length, and the middle phalanx of both little fingers is reduced in
length. There is a bifurcation of the ungual phalanx of the index finger of the
left hand, an anomaly mentioned by Cunningham, and a similar bifurcation
appears to be present in the other index, but the phalanx is very slender.

In the feet there is no syndactyly and no visible deformity, but the skiagrams show that the middle phalanx of both second toes is absent. Only two
bones are present in each little toe, but this is probably normal, as the proximal
and middle phalanges are often fused.
166 E. A. Cockayne

Skiagrams taken on 25 February, 1982, when the boy was 13 months old,
show the arrangement of the abnormal bones more clearly. In the right hand
the proximal phalanx of the middle finger appears to be replaced by three
bones on the radial side, the largest of which articulates with the middle phalanx
and three on the ulnar side. The latter group is very little further away from
the metacarpal than the most proximal of the radial group and much nearer
to it than the two others belonging to the radial group. In the left hand there
are two groups of very small bones replacing the proximal phalanx of the
middle finger, but it is difficult to be sure whether there are three in each group
or only two, though I think there are three. The position of those on the ulnar
side corresponds in the two hands, but on the radial side the group in the left
hand is intermediate in position between the two nearest to the middle phalanx
and the one nearest to the metacarpal in the right hand.

I have never met this form of brachyphalangy before, nor have I seen any
published description of it. In some respects it resembles the condition described by Drinkwater under the title “Hereditary Abnormal Segmentation
of the Index and Middle Fingers.” In this there is remarkable reduction in the
length of the index and middle fingers and the middle phalanx of the index is
aborted. In the index there is a bone of approximately the same length as the
proximal phalanx lying between it and the head of the second metacarpal and.
becoming fused with the proximal phalanx in adult life, and in the middle
finger a triangular bone is interposed on the radial side between the proximal
phalanx and the head of the third metacarpal and becomes fused with the
phalanx in later life. Drinkwater regards these bones as extra bones arising
from an abnormal division of the primitive mesenchyme. Though different in
position they may be compared with the extra bones in the position of the
proximal phalanx of the middle fingers of my patient. These are looked upon
by Dr Bertram Shires, to whom I am indebted for the skiagrams, as extra
bones, and he thinks that there is a double phalanx. If so the cause is probably
another kind of abnormal division of the mesenchyme in early embryonic life.
Drinkwater’s patients had no syndactyly, the feet showed ordinary brachydactyly, the abnormality was inherited as a simple dominant, and so
the condition differed in all these three respects from that present in my
patient.

Olaf Thomsen has described as the Vordingborg type a syndactyly of the
middle and ring fingers with partial or complete doubling of the middle fingers.
In some cases the middle phalanx and in others the third metacarpal is branched
and all the parts distal to the bifurcation are doubled. Sometimes, however,
instead of a simple branching of the metacarpal there is an isolated bone
opposite the base of the branched phalanx or the head of the single metacarpal
and this bone probably represents part of an extra metacarpal. The condition
agrees with that seen in my patient in the association of syndactyly with reduplication of parts, but the reduplication is much more complete and different
in character. It differs in the absence of brachyphalangy and in its mode of
Journal of Anatomy, Vol. LX VII, Part 1 Plate I

 

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COCKAYNE—BracnyPHaLaNGy AND SYNDACTYLY
Brachyphalangy and Syndactyly 167

inheritance. Males are affected more often than females, and up to the present
_time it has been transmitted only by males. It is evidently a dominant.

Though differing in minor points the defects in the hands and feet of this
boy are in the main symmetrical and this bilateral symmetry makes it almost
certain that the abnormality is genetic in origin. It is indeed common to find
much greater asymmetry in inherited osseous defects of the extremities. A
number of distinct forms of brachyphalangy and of syndactyly occurring either
alone or in combination have been described, but with one exception all those
with which I am acquainted are autosomal dominants. The one exception is
the form of syndactyly described by Schofield, which is transmitted by males
only to all their sons and is probably due to a gene in the Y-chromosome.
Since the parents of this boy are normal the defect cannot be dominant unless
it arose as anew mutation, but it may be recessive, and the fact that the parents
are first cousins makes this very probable.

For whereas amongst the general population the percentage of marriages
between first cousins is on the average 0-5-1 per cent., in the case of those that
give rise to one or more children with a recessive defect the percentage rises
from 17 in the case of a relatively common one, such as albinism, to 50 or more,
and the rarer the defect the higher is the percentage of first cousin marriages
giving rise to it. Thus the high percentage of first cousin marriages in the parents
is the most reliable indication that a defect is recessive. Though no safe deduction can be drawn from a single case, we have here a rare defect apparently
of genetic origin in the child of first cousins, and the suspicion at once arises
that it may be recessive. The case is therefore worth recording, for it is only by
publishing descriptions of single cases with full family histories that the mode
of inheritance of rare recessive abnormalities can be proved. No single observer can hope to see enough cases himself, but if single cases are published
sufficient data can be collected from the literature in course of time, and I hope
this short paper will lead to the publication of other cases of the same kind.

REFERENCES

Drinkwater, H. (1915-16). J. Anat. and Physiol. vol. u, p. 177.
TxomseEn, O. (1926-7). Acta Scandinavica, vol. Lxv, p. 609; vol. LxvI, p. 588.