Carpenter syndrome is a rare autosomal recessive disorder with the cardinal features of acrocephaly with variable synostosis of the sagittal, lambdoid, and coronal sutures; peculiar facies; brachydactyly of the hands with syndactyly; preaxial polydactyly and syndactyly of the ... Carpenter syndrome is a rare autosomal recessive disorder with the cardinal features of acrocephaly with variable synostosis of the sagittal, lambdoid, and coronal sutures; peculiar facies; brachydactyly of the hands with syndactyly; preaxial polydactyly and syndactyly of the feet; congenital heart defects; growth retardation; mental retardation; hypogenitalism; and obesity. In addition, cerebral malformations, oral and dental abnormalities, coxa valga, genu valgum, hydronephrosis, precocious puberty, and hearing loss may be observed (summary by Altunhan et al., 2011). - Genetic Heterogeneity of Carpenter Syndrome Carpenter syndrome-2 (CRPT2; 614976), in which the features of Carpenter syndrome are sometimes associated with defective lateralization, is caused by mutation in the MEGF8 gene (604267).
Carpenter (1909) described 2 sisters and a brother with acrocephaly, peculiar facies, brachydactyly, and syndactyly in the hands, and preaxial polydactyly and syndactyly of the toes. Temtamy (1966) could find 9 other reported cases and added one. In ... Carpenter (1909) described 2 sisters and a brother with acrocephaly, peculiar facies, brachydactyly, and syndactyly in the hands, and preaxial polydactyly and syndactyly of the toes. Temtamy (1966) could find 9 other reported cases and added one. In older patients obesity, mental retardation, and hypogonadism had been noted. In all cases the parents have been normal. Parental consanguinity was suspected in 1 case. The case of acrocephalosyndactyly with foot polydactyly reported by Owen (1952) probably represented Carpenter syndrome, as do the sibs reported by Schonenberg and Scheidhauer (1966). One patient thought to have this condition by Palacios and Schimke (1969) was 49 years old. Eaton et al. (1974) reported affected sibs. Cohen et al. (1987) described 2 affected sibs showing marked intrafamilial variability. This experience and a review of the literature suggested that the Goodman syndrome (201020) and the Summitt syndrome (272350) fall well within the clinical spectrum of the Carpenter syndrome. Gershoni-Baruch (1990) described a brother and sister with rather striking differences in severity. The first born had craniosynostosis of the sagittal suture, normal intelligence, and no abnormalities of the hands and feet. The second born sib had polysyndactyly of hands and feet, normal intelligence, and no craniosynostosis. Gershoni-Baruch (1990) suggested that polysyndactyly is not an absolute requisite for the diagnosis of Carpenter syndrome and that the Summitt and Goodman syndromes are 'within the clinical spectrum' of Carpenter syndrome, as suggested by Cohen et al. (1987). Alessandri et al. (2010) described 4 boys with Carpenter syndrome from a consanguineous Comoros Islands pedigree. All 4 boys presented with acrocephaly and polysyndactyly, but displayed variable severity of craniosynostosis ranging from cloverleaf skull to predominant involvement of the metopic ridge (turricephaly). All of the children also had a combination of brachydactyly with agenesis of the middle phalanges, syndactyly, broad thumbs, and postaxial polydactyly in the hands, with preaxial polydactyly and syndactyly of the toes. Mental development was normal in all; brain imaging showed hydrocephalus in 2 of the 4 boys. Additional features included corneal anomaly in 2, cryptorchidism in 3, umbilical hernia in 1, genu valgum in 2, umbilical hernia in 1, severe kyphoscoliosis in 1, patent ductus arteriosus in 1, and accessory spleen in 1.
In 15 independent families with Carpenter syndrome, Jenkins et al. (2007) identified 5 different mutations (4 truncating and 1 missense) in the RAB23 gene (see, e.g., L145X, 606144.0001; 606144.0002), which encodes a member of the RAB guanosine triphosphatase ... In 15 independent families with Carpenter syndrome, Jenkins et al. (2007) identified 5 different mutations (4 truncating and 1 missense) in the RAB23 gene (see, e.g., L145X, 606144.0001; 606144.0002), which encodes a member of the RAB guanosine triphosphatase (GTPase) family of vesicle transport proteins and acts as a negative regulator of hedgehog (HH) signaling (see 600725). In 10 patients, the disease was caused by homozygosity for the same L145X mutation that resides on a common haplotype, indicative of a founder effect in patients of northern European descent. In 4 boys with Carpenter syndrome from a consanguineous Comoros Islands pedigree, Alessandri et al. (2010) identified homozygosity for a 1-bp duplication in the RAB23 gene (606144.0003).