Saethre-Chotzen syndrome is one of the most common autosomal dominant disorders of craniosynostosis in humans and is characterized by craniofacial and limb anomalies. The locus for Saethre-Chotzen syndrome maps to chromosome 7p21-p22. We have evaluated TWIST, a basic helix-loop-helix transcription factor, as a candidate gene for this condition because its expression pattern and mutant phenotypes in Drosophila and mouse are consistent with the Saethre-Chotzen phenotype. We mapped TWIST to human chromosome 7p21-p22 and mutational analysis reveals nonsense, missense, insertion and deletion mutations in patients. These mutations occur within the basic DNA binding, helix I and loop domains, or result in premature termination of the protein. Studies in Drosophila indicate that twist may affect the transcription of fibroblast growth factor receptors (FGFRs), another gene family implicated in human craniosynostosis. The emerging cascade of molecular components involved in craniofacial and limb development now includes TWIST, which may function as an upstream regulator of FGFRs.

The spotted eagle ray Aetobatus narinari is characterized by pigmentation patterns that are retained for up to 3·5 years. These pigmentations can be used to identify individuals through photo-identification. Only one study has validated this technique, but no study has estimated the percentage of correct identification of the rays using this technique. In order to carry out demographic research, a reliable photographic identification technique is needed. To achieve this validation for A. narinari, a double-mark system was established over 11 months and photographs of the dorsal surface of 191 rays were taken. Three body parts with distinctive natural patterns were analysed (dorsal surface of the cephalic region, dorsal surface of the pectoral fins and dorsal surface of the pelvic fins) in order to determine the body part that could be used to give the highest percentage of correct identification. The dorsal surface of the pectoral fins of A. narinari provides the most accurate photo-identification to distinguish individuals (88·2%).

This paper describes 3 infants with a severe, generalized chondrodysplasia with short limbs, shortness of stature, relative micrognathia and neonatal respiratory distress in all cases, cleft palate in two and dislocation of lenses in one. They died at 7 and 10 weeks and at 17 months respectively. No autopsy was performed on any of the 3 patients. Roentgenological manifestations include short, broad tubular bones with metaphyseal widening, bowing of leg, thigh and forearm bones, neonatal accelerated carpal bone maturation, short, broad pelvis with wide, flared iliac wings, many gross vertebral abnormalities including most prominently coronal clefts of almost any vertebral body, and short ribs with flared anterior ends. Roentgenographically the condition has some similarities with Kniest disease, or more correctly, the Kniest chondrodysplasia. However, we think that the clinical and roentgenological manifestations are sufficiently unique to permit delineation of the condition of our 3 patients as a "new" entity different from the Kniest chondrodysplasia. Similar cases have been described by Rolland et al. from France and by Dinno et al. from the U.S.A. The later case and our 3 patients were sporadic cases, but the former had a probably affected sibling, suggesting that this disorder is an autosomal recessive trait.

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