Ca. Murdochkinch et Re. Ward, METACARPOPHALANGEAL ANALYSIS IN CROUZON-SYNDROME - ADDITIONAL EVIDENCE FOR PHENOTYPIC CONVERGENCE WITH THE ACROCEPHALOSYNDACTYLY SYNDROMES, American journal of medical genetics, 73(1), 1997, pp. 61-66
Crouzon syndrome (CS) is characterized by premature craniosynostosis,
orbital proptosis, and midfacial hypoplasia and is related to the acro
cephalosyndactylies (ACS) with limb abnormalities. In CS the hands are
considered to be normal, but a previous report indicated that there i
s consistent alteration in the proportions of the bones of the hands,
as shown by metacarpophalangeal analysis (MCPP), in at least some case
s of CS, The purpose of this study was to extend these findings by exa
mining affected individuals and their supposedly unaffected first degr
ee relatives. If CS does have an effect on hands, then this should onl
y be evident in the affected individuals and, presuming complete penet
rance, not present in their unaffected relatives, PA hand films were t
aken on 12 CS subjects and 16 of their normal relatives. The lengths o
f the metacarpals and phalanges were measured and the measurements sta
ndardized for age and sex by conversion to z-scores using published no
rmal standards. Mean pattern profiles for the 2 groups were plotted, I
n CS the phalanges, especially the first and second proximal phalanges
and the first distal phalanx, were shorter than average, and shorter
than those of unaffected relatives, The metacarpals were not significa
ntly smaller than the reference means in CS, The 19 hand measurements
were entered into a stepwise forward discriminant function analysis (D
FA) to develop a model that would discriminate between CS subjects and
their normal first degree relatives, The function generated used the
measurements of 8 hand bones to classify correctly CS subjects and the
ir normal relatives 100% of the time, This study confirmed that there
is a radiographically detectable abnormality of the hands in CS and th
at, at least in this sample, relatives did not display such abnormalit
ies. Therefore, it seems that CS shares postcranial effects with true
ACS and that these effects are, like the other aspects of CS, fully pe
netrant. (C) 1997 Wiley-Liss, Inc.