WNT1 mutations in early-onset osteoporosis and osteogenesis imperfecta.

This report identifies human skeletal diseases associated with mutations in WNT1. In 10 family members with dominantly inherited, early-onset osteoporosis, we identified a heterozygous missense mutation in WNT1, c.652T→G (p.Cys218Gly). In a separate family with 2 siblings affected by recessive osteogenesis imperfecta, we identified a homozygous nonsense mutation, c.884C→A, p.Ser295*. In vitro, aberrant forms of the WNT1 protein showed impaired capacity to induce canonical WNT signaling, their target genes, and mineralization. In mice, Wnt1 was clearly expressed in bone marrow, especially in B-cell lineage and hematopoietic progenitors; lineage tracing identified the expression of the gene in a subset of osteocytes, suggesting the presence of altered cross-talk in WNT signaling between the hematopoietic and osteoblastic lineage cells in these diseases.

Beyond Gómez-López-Hernández syndrome: recurring phenotypic themes in rhombencephalosynapsis.

Rhombencephalosynapsis (RES) is an uncommon cerebellar malformation characterized by fusion of the hemispheres without an intervening vermis. Frequently described in association with Gómez-López-Hernández syndrome, RES also occurs in conjunction with VACTERL features and with holoprosencephaly (HPE). We sought to determine the full phenotypic spectrum of RES in a large cohort of patients. Information was obtained through database review, patient questionnaire, radiographic, and morphologic assessment, and statistical analysis. We assessed 53 patients. Thirty-three had alopecia, 3 had trigeminal anesthesia, 14 had VACTERL features, and 2 had HPE with aventriculy. Specific craniofacial features were seen throughout the cohort, but were more common in patients with alopecia. We noted substantial overlap between groups. We conclude that although some distinct subgroups can be delineated, the overlapping features seen in our cohort suggest an underlying spectrum of RES-associated malformations rather than a collection of discrete syndromes.

Holoprosencephaly and agnathia spectrum: Presentation of two new patients and review of the literature.

Holoprosencephaly (HPE), the most common developmental disorder of the human forebrain, is occasionally associated with the spectrum of agnathia, or virtual absence of the mandible. This condition results in a constellation of structural cerebral and craniofacial abnormalities. Here we present two new patients and review 30 patients from the literature with HPE and variants of agnathia. The majority of these patients are female and have the most severe forms of HPE, with cyclopia present more frequently than is usually observed in cohorts of patients with HPE. Also, many patients have additional clinical findings not typical in patients with classic HPE, particularly situs abnormalities. Recent animal studies suggest that the association of HPE and agnathia may relate to alterations in signaling from forebrain and foregut endoderm organizing centers and subsequent first pharyngeal arch development, although present models are inadequate to explain all of the clinical findings of this enigmatic human syndrome. Further research is required to better elucidate the causal and pathogenic basis of this association.

Elements of morphology: standard terminology for the lips, mouth, and oral region.

An international group of clinicians and scientists working in the field of dysmorphology has initiated the standardization of terms used to describe human morphology. The goals are to standardize these terms and reach consensus regarding their definitions. In this way, we will increase the utility of descriptions of the human phenotype and facilitate reliable comparisons of findings among patients. Discussions with other workers in dysmorphology and related fields, such as developmental biology and molecular genetics, will become more precise. Here we summarize the anatomy of the oral region and define and illustrate the terms that describe the major characteristics of the lips and mouth.

Chondrodysplasia punctata associated with maternal autoimmune diseases: expanding the spectrum from systemic lupus erythematosus (SLE) to mixed connective tissue disease (MCTD) and scleroderma report of eight cases.

Chondrodysplasia punctata (CDP) is etiologically a heterogeneous condition and has been associated with single gene disorders, chromosome abnormalities and teratogenic exposures. The first publication of the association between CDP and maternal autoimmune connective tissue disorder was by Curry et al. 1993]. Chondrodysplasia punctata associated with maternal collagen vascular disease. A new etiology? Presented at the David W. Smith Workshop on Morphogenesis and Malformations, Mont Tremblant, Quebec, August 1993] and subsequently, other cases have been reported. We report on eight cases of maternal collagen vascular disease associated with fetal CDP and included the cases reported by Curry et al. 1993. Chondrodysplasia punctata associated with maternal collagen vascular disease. A new etiology? Presented at the David W. Smith Workshop on Morphogenesis and Malformations, Mont Tremblant, Quebec, August 1993] and Costa et al. [1993]. Maternal systemic lupus erythematosis (SLE) and chondrodysplasia punctata in two infants. Coincidence or association? 1st Meeting of Bone Dysplasia Society, Chicago, June 1993] which were reported in an abstract form. We suggest that maternal autoimmune diseases should be part of the differential diagnosis and investigation in newborns/fetuses with CDP. Thus, in addition to cardiac evaluation, fetuses/newborn to mothers with autoimmune diseases should have fetal ultrasound/newborn examination and if indicated, X-rays, looking for absent/hypoplastic nasal bone, brachydactyly, shortened long bones and epiphyseal stippling.

Consistent chromosome abnormalities identify novel polymicrogyria loci in 1p36.3, 2p16.1-p23.1, 4q21.21-q22.1, 6q26-q27, and 21q2.

Polymicrogyria is a malformation of cortical development characterized by loss of the normal gyral pattern, which is replaced by many small and infolded gyri separated by shallow, partly fused sulci, and loss of middle cortical layers. The pathogenesis is unknown, yet emerging data supports the existence of several loci in the human genome. We report on the clinical and brain imaging features, and results of cytogenetic and molecular genetic studies in 29 patients with polymicrogyria associated with structural chromosome rearrangements. Our data map new polymicrogyria loci in chromosomes 1p36.3, 2p16.1-p23, 4q21.21-q22.1, 6q26-q27, and 21q21.3-q22.1, and possible loci in 1q44 and 18p as well. Most and possibly all of these loci demonstrate incomplete penetrance and variable expressivity. We anticipate that these data will serve as the basis for ongoing efforts to identify the causal genes located in these regions.

Neonatal phenotype in Kabuki syndrome.

The Kabuki syndrome is a well-established pattern of human malformation with readily recognizable features, however the diagnosis is rarely made in the newborn period. The purpose of this study was to determine if there exists a neonatal phenotype for this disorder. We ascertained 16 infants evaluated in the first 28 days of life by a dysmorphologist who subsequently received the diagnosis of Kabuki syndrome. The average age of initial evaluation was 8 days and the average age of diagnosis was 2 years 6 months. Based on these findings, it is suggested that the distinctive clinical phenotype seen in older patients is also evident in the newborn period.

Spectrum of dolichospondylic dysplasia: two new patients with distinctive findings.

Dolichospondylic dysplasia (DD) is a rare skeletal dysplasia primarily characterized by tall vertebral bodies and disproportionate short stature. Radiographic manifestations include tall vertebral bodies and gracile bones of the hands. Patients usually have eye and ear findings in addition to borderline mental retardation; however, tall vertebral bodies and slender tubular bones are also seen in the 3-M syndrome. Patients with the 3-M syndrome have a characteristic face with a triangular shape, frontal bossing, a flattened malar region, full eyebrows, a short nose with a bulbous tip, upturned nares, and full lips. We present two unrelated patients who share a distinct phenotype and have tall vertebral bodies, overtubulation of long bones, and short tubular bones of the hands and feet. We discuss the overlapping and distinguishing features between DD and the 3-M syndrome. Patient 1 was a 13-year-old female, and patient 2 was an unrelated adult female. These patients had normocephaly and short stature. They shared a common phenotype consisting of mild malar hypoplasia, a narrowed nasal body with a fleshy tip, full lips, and normal intelligence. In addition, they showed mild hand and foot abnormalities. These two patients lack many of the typical clinical features of both DD and the 3-M syndrome. They share a common phenotype and likely represent a distinct disorder. The spectrum of disorders with tall vertebral bodies as a key feature may include different entities that may be further defined with the characterization of the molecular defect(s).