Sensorineural deafness, enamel abnormalities and nail abnormalities: a case report of Heimler syndrome in identical twin girls.

We report monozygotic twin girls with a combination of bilateral severe sensorineural deafness diagnosed at the age of 3 years, normal primary dentition but enamel hypoplasia affecting the secondary dentition and Beau's lines and leukonychia of the nails. This constellation of findings has been previously described in three case reports as Heimler syndrome, first documented in 1991.

Apparent cleidocranial dysplasia associated with abnormalities of 8q22 in three individuals.

Cleidocranial dysplasia is an autosomal dominant, generalised skeletal disorder characterised by variable clavicular hypoplasia, frontal bossing, multiple Wormian bones, and delayed eruption of the teeth. The gene locus for this syndrome has not yet been assigned. Three individuals with manifestations of cleidocranial dysplasia associated with rearrangements of chromosome 8q22 are described. The evidence presented suggests that the gene for cleidocranial dysplasia may be located on chromosome 8q in humans in a region showing homology to mouse chromosome 3.

Hypoplastic thumb in Gorlin's syndrome.

Gorlin's syndrome or naevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder that predisposes to basal cell carcinomas of the skin, ovarian fibromas, and medulloblastomas. This condition is due to mutations in the Patched (PTCH) gene which maps to chromosome 9q22 and acts as a tumour suppressor gene. Gorlin's syndrome is characterized by the development of multiple jaw keratocysts and/or basal carcinomas. There is a distinctive coarse facial appearance with macrocephaly, frontal bossing and prognathism. Most individuals have skeletal anomalies such as bifid ribs or wedge-shaped vertebrae. We present a case in which the patient presented with bilateral thumb hypoplasia. Various hand deformities have been reported in patients with Gorlin's syndrome including short metacarpals, cutaneous syndactyly of the second and third fingers, and pre- or post-axial polydactyly, but hypoplasia of the thumb has not been reported previously. These features of Gorlin's syndrome may be helpful diagnostically. The thumbs should be examined carefully in Gorlin's syndrome patients as minor degrees of hypoplasia are easy to miss. However, they still needs a specialist input to give the patient an optimum function of the thumb and the hand.

Localization of a gene for oculodentodigital syndrome to human chromosome 6q22-q24.

Oculodentodigital syndrome (ODD) is a congenital, autosomal dominant disorder which affects the development of the face, eyes, limbs and dentition. Spastic paraparesis is thought to be an occasional manifestation of the disorder. Type III syndactyly, which occurs as part of ODD, has also been reported to occur as an isolated entity. In the current investigation, a total genome search for the location of the ODD locus was instigated and linkage to polymorphic markers located on chromosome 6q established (pairwise Zmax = 9.37; theta = 0.001). Analysis of a large family with type III syndactyly, but atypical facial features, further suggested that isolated type III syndactyly is also located in this same region of the genome.

A gene for cleidocranial dysplasia maps to the short arm of chromosome 6.

Cleidocranial dysplasia (CCD) is an autosomal dominant generalized bone dysplasia characterized by mild-to-moderate short stature, clavicular aplasia or hypoplasia, supernumerary and ectopic teeth, delayed eruption of secondary teeth, a characteristic craniofacial appearance, and a variety of other skeletal anomalies. We have performed linkage studies in five families with CCD, with 24 affected and 20 unaffected individuals, using microsatellite markers spanning two candidate regions on chromosomes 8q and 6. The strongest support for linkage was with chromosome 6p microsatellite marker D6S282 with a two-point lod score of 4.84 (theta = .03). Furthermore, the multipoint lod score was 5.70 in the interval between D6S282 and D6S291. These data show that the gene for autosomal dominant CCD is located within a 19-cM interval on the short arm of chromosome 6, between D6S282 and D6S291.

Mutation analysis of core binding factor A1 in patients with cleidocranial dysplasia.

Cleidocranial dysplasia (CCD) is a dominantly inherited disorder characterized by patent fontanelles, wide cranial sutures, hypoplasia of clavicles, short stature, supernumerary teeth, and other skeletal anomalies. We recently demonstrated that mutations in the transcription factor CBFA1, on chromosome 6p21, are associated with CCD. We have now analyzed the CBFA1 gene in 42 unrelated patients with CCD. In 18 patients, mutations were detected in the coding region of the CBFA1 gene, including 8 frameshift, 2 nonsense, and 9 missense mutations, as well as 2 novel polymorphisms. A cluster of missense mutations at arginine 225 (R225) identifies this residue as crucial for CBFA1 function. In vitro green fluorescent protein fusion studies show that R225 mutations interfere with nuclear accumulation of CBFA1 protein. There is no phenotypic difference between patients with deletions or frameshifts and those with other intragenic mutations, suggesting that CCD is generally caused by haploinsufficiency. However, we were able to extend the CCD phenotypic spectrum. A missense mutation identified in one family with supernumerary teeth and a radiologically normal skeleton indicates that mutations in CBFA1 can be associated exclusively with a dental phenotype. In addition, one patient with severe CCD and a frameshift mutation in codon 402 had osteoporosis leading to recurrent bone fractures and scoliosis, providing first evidence that CBFA1 may help maintain adult bone, in addition to its function in bone development.