Chromosome 1p36.22p36.21 duplications/triplication causes Setleis syndrome (focal facial dermal dysplasia type III).

Focal facial dermal dysplasias (FFDD) are characterized by congenital bitemporal or preauricular atrophic skin lesions, and either autosomal dominant or autosomal recessive inheritance. Setleis syndrome (SS), FFDD type III, is a severe form of FFDD with the ectodermal lesions plus other striking facial features. Autosomal recessive nonsense and frameshift mutations in TWIST2 have been found to cause SS in some but not all individuals. Here, we report on four unrelated individuals, one with an unclassified FFDD and the other three with classic SS. Chromosomal microarray analyses revealed unique copy number variants of 1p36 in two individuals with duplications at 1p36.22p36.21 and one with a triplication at 1p36.22p36.21. The fourth patient had normal chromosomes by microarray analysis. All four patients had normal TWIST2 exonic sequences. We propose that a dosage effect of one or more of the 30 genes in the 1.3 Mb 1p36.22p36.21 region of overlap is responsible for FFDD/SS manifestations in some individuals, and this mechanism would be inherited as an autosomal dominant trait. In patients with no duplication/triplication of the 1p36.22p36.21 region and no mutations in TWIST2, there are mutation(s) in one of the 30 genes in this region or mutations in other as yet unidentified genes at different locations that may affect the expressions of genes in this region or act independently to cause this developmental disease phenotype.

Fibrochondrogenesis results from mutations in the COL11A1 type XI collagen gene.

Fibrochondrogenesis is a severe, autosomal-recessive, short-limbed skeletal dysplasia. In a single case of fibrochondrogenesis, whole-genome SNP genotyping identified unknown ancestral consanguinity by detecting three autozygous regions. Because of the predominantly skeletal nature of the phenotype, the 389 genes localized to the autozygous intervals were prioritized for mutation analysis by correlation of their expression with known cartilage-selective genes via the UCLA Gene Expression Tool, UGET. The gene encoding the α1 chain of type XI collagen (COL11A1) was the only cartilage-selective gene among the three candidate intervals. Sequence analysis of COL11A1 in two genetically independent fibrochondrogenesis cases demonstrated that each was a compound heterozygote for a loss-of-function mutation on one allele and a mutation predicting substitution for a conserved triple-helical glycine residue on the other. The parents who were carriers of missense mutations had myopia. Early-onset hearing loss was noted in both parents who carried a loss-of-function allele, suggesting COL11A1 as a locus for mild, dominantly inherited hearing loss. These findings identify COL11A1 as a locus for fibrochondrogenesis and indicate that there might be phenotypic manifestations among carriers.

Polyhydramnios, fetal overgrowth, and macrocephaly: prenatal ultrasound findings of Costello syndrome.

Costello syndrome is a multiple congenital anomaly syndrome consisting of dysmorphic facies, cutis laxa, short stature, developmental delay, and mental retardation. Complications include failure to thrive, hypertrophic cardiomyopathy with arrhythmias, and benign and malignant tumors. This report describes a new case of Costello syndrome in a preterm infant born at 27 weeks gestation and diagnosed with Costello syndrome at 7 weeks of life who died at 6 months of age due to cardiac and pulmonary complications. In addition, data were compiled from parent surveys including growth parameters on 16 infants who were subsequently diagnosed with Costello syndrome and had mutation confirmation. The most common prenatal findings in the literature and in this cohort were polyhydramnios and fetal overgrowth with relative macrocephaly. Based on this study, ultrasound identification of polyhydramnios in the context of prenatal overgrowth, especially with relative macrocephaly, needs to raise the possibility of a diagnosis of Costello syndrome in the fetus because of the life-threatening cardiac complications that may occur early in the newborn period.

Hardikar syndrome: new features.

Hardikar syndrome (HS) is a disorder of multiple anomalies predominantly characterized by cleft lip/palate, liver and biliary tract disease, intestinal malrotation, obstructive uropathy, and retinopathy. To date, three patients have been reported with the unusual constellation of chronic liver/biliary tract disease and obvious defects in organogenesis [Hardikar et al. (1992): Am J Med Genet 44: 13-17; Cools and Jaeken (1997): Am J Med Genet 71: 472-474]. With this report, we add another patient with this syndrome. New features, hitherto not reported, were vaginal atresia, a type 1 choledochal cyst and, owing to the progressive nature of the liver disease, the need for liver transplantation. It is intriguing to speculate, that HS could be genetically related to Alagille syndrome (AS), since both conditions share an unusual number of phenotypic abnormalities.

Mutations of ARX are associated with striking pleiotropy and consistent genotype-phenotype correlation.

We recently identified mutations of ARX in nine genotypic males with X-linked lissencephaly with abnormal genitalia (XLAG), and in several female relatives with isolated agenesis of the corpus callosum (ACC). We now report 13 novel and two recurrent mutations of ARX, and one nucleotide change of uncertain significance in 20 genotypic males from 16 families. Most had XLAG, but two had hydranencephaly and abnormal genitalia, and three males from one family had Proud syndrome or ACC with abnormal genitalia. We obtained detailed clinical information on all 29 affected males, including the nine previously reported subjects. Premature termination mutations consisting of large deletions, frameshifts, nonsense mutations, and splice site mutations in exons 1 to 4 caused XLAG or hydranencephaly with abnormal genitalia. Nonconservative missense mutations within the homeobox caused less severe XLAG, while conservative substitution in the homeodomain caused Proud syndrome. A nonconservative missense mutation near the C-terminal aristaless domain caused unusually severe XLAG with microcephaly and mild cerebellar hypoplasia. In addition, several less severe phenotypes without malformations have been reported, including mental retardation with cryptogenic infantile spasms (West syndrome), other seizure types, dystonia or autism, and nonsyndromic mental retardation. The ARX mutations associated with these phenotypes have included polyalanine expansions or duplications, missense mutations, and one deletion of exon 5. Together, the group of phenotypes associated with ARX mutations demonstrates remarkable pleiotropy, but also comprises a nearly continuous series of developmental disorders that begins with hydranencephaly, lissencephaly, and agenesis of the corpus callosum, and ends with a series of overlapping syndromes with apparently normal brain structure.

Advancing our understanding of the inheritance and transmission of pectus excavatum.

Pectus excavatum is the most common congenital chest wall abnormality expressed in children, yet its inheritance is poorly understood. Here we present the first comprehensive assessment of the inheritance of this disorder. After evaluating 48 pedigrees and 56 clinical traits of probands and family members, we find strong evidence of autosomal recessive, genetic control for this disorder. Additionally there is likely more than one pectus disease-associated allele, as well as a relatively large number of disease allele carriers in the human population. Some clinical traits appear important and may serve as reliable indicators for predicting the likelihood of pectus excavatum in children before severe symptoms present. Quantifying sex-ratio bias in probands demonstrates a highly significant male bias associated with pectus excavatum. When combined with pedigree data, sex-bias is indicative of sex-linked, sex-limited, and/or epigenetic control such as X-inactivation, reiterating a point made with pedigrees alone, which is that more than one mutation is likely responsible for this disorder.

Avoiding transmitting identified mutations to offspring using preimplantation genetic diagnosis.

BACKGROUND: Preimplantation genetic diagnosis has been used to decrease or avoid the risk of transmitting identified mutations to offspring. CASE: A 29-year-old woman with spondyloepiphyseal dysplasia congenita and her 30-year-old husband with Marfan syndrome underwent in vitro fertilization with preimplantation genetic diagnosis. Two mutation-negative embryos were transferred into a gestational carrier, who became pregnant with twins and delivered two clinically normal neonates. CONCLUSION: Statistically, this couple would be predicted to have a 75% chance of producing an affected embryo. Using preimplantation genetic diagnosis, two dually unaffected embryos were selected and transferred. This experience expands the use of preimplantation genetic diagnosis to cases with multiple autosomal dominant single-gene disorders.

Classification of the dysmorphology of pectus excavatum.

BACKGROUND/PURPOSE: To describe the dysmorphology of pectus excavatum, the most common congenital chest wall anomaly. METHODS: A stratified sample of 64 patients, representative of a patient population with pectus excavatum of the Children's Hospital of King's Daughters in Norfolk, VA, was described and classified. The sample was stratified by sex to represent a 4:1 male-to-female ratio. The sample was further stratified to represent categories of age (3-10, 11-16, and 17 years and older). Preoperative photos and baseline chest computed tomography scans were examined and categorized according to the chief criteria, including asymmetry/symmetry of the depression, localized vs diffuse morphology, sternal torsion, cause of asymmetric appearance, and the length of the depression. RESULTS: Useful morphologic distinctions in pectus excavatum are localized depressions vs diffuse depressions, short and long length, symmetry, sternal torsion, slope/position of absolute depth, and unique patterns such as the horns of steer depression. CONCLUSIONS: These classifications simplify the diagnosis of pectus excavatum, aid in corrective surgery, and should improve correlation of phenotype and genotype in future genetic analysis.

Family study of the inheritance of pectus excavatum.

BACKGROUND: The most common congenital deformity of the chest wall is pectus excavatum, a malformation that is present in between 1 in 400 and 1 in 1000 live births and causes the body of the sternum to be displaced, producing a depression. There are many different shapes of the pectus, and multiple factors probably contribute to the final form. The etiology of pectus excavatum is uncertain, but a familial tendency has been found in clinical experience, where it may be seen in more than one sibling. Pectus excavatum is commonly associated with connective tissue disorders such as Marfan and Ehlers Danlos syndromes. Extensive literature review failed to identify articles documenting families with multiple affected members. PURPOSE: The purpose of this study was to collect evidence that pectus excavatum is familial and may be an inherited disorder. METHODS: Using the Children's Surgical Specialty Group database at Children's Hospital of The King's Daughters, families with more than one affected individual were selected. With Institutional Review Board-approved informed consent, 34 families agreed to participate. Family histories were obtained, and a 4-generation pedigree was constructed for each family. Forty questions were asked about each individual's medical history, and comprehensive systems review included features of connective tissue-related problems. Inheritance patterns for each family were determined by pedigree analysis. RESULTS: A total of 14 families suggested autosomal dominant inheritance, 4 families suggested autosomal recessive inheritance, and 6 families suggested X-linked recessive inheritance. Ten families had complex inheritance patterns. Pectus excavatum occurred more frequently in males than in females (1.8:1). Long arms, legs, and fingers; high-arched palate; mitral valve prolapse; heart arrhythmia; scoliosis; double jointedness; flexibility; flat feet; childhood myopia; poor healing; and easy bruising were commonly associated with pectus excavatum. CONCLUSIONS: Pedigree analysis of 34 families provides evidence that pectus excavatum is an inherited disorder, possibly of connective tissue. Although some families demonstrate apparent Mendelian inheritance, most appear to be multifactorial.

Trismus-pseudocamptodactyly syndrome is caused by recurrent mutation of MYH8.

Trismus-pseudocamptodactyly syndrome (TPS) is a rare autosomal dominant distal arthrogryposis (DA) characterized by an inability to open the mouth fully (trismus) and an unusual camptodactyly of the fingers that is apparent only upon dorsiflexion of the wrist (i.e., pseudocamptodactyly). TPS is also known as Dutch-Kentucky syndrome because a Dutch founder mutation is presumed to be the origin of TPS cases in the Southeast US, including Kentucky. To date only a single mutation, p.R674Q, in MYH8 has been reported to cause TPS. Several individuals with this mutation also had a so-called "variant" of Carney complex, suggesting that the pathogenesis of TPS and Carney complex might be shared. We screened MYH8 in four TPS pedigrees, including the original Dutch family in which TPS was reported. All four TPS families shared the p.R674Q substitution. However, haplotype analysis revealed that this mutation has arisen independently in North American and European TPS pedigrees. None of the individuals with TPS studied had features of Carney complex, and p.R674Q was not found in 49 independent cases of Carney complex that were screened. Our findings show that distal arthrogryposis syndromes share a similar pathogenesis and are, in general, caused by disruption of the contractile complex of muscle.

Pacman dysplasia: a lethal skeletal dysplasia with variable radiographic features.

BACKGROUND: Punctate or stippled cartilaginous calcifications are associated with many conditions, including chromosomal, infectious, endocrine, and teratogenic etiologies. Some of these conditions are clinically mild, while others are lethal. Accurate diagnosis can prove instrumental in clinical management and in genetic counseling. OBJECTIVE: To describe the diagnostic radiographic features seen in Pacman dysplasia, a distinct autosomal recessive, lethal skeletal dysplasia. MATERIALS AND METHODS: We present the fourth reported case of Pacman dysplasia and compare the findings seen in our patient with the three previously described patients. RESULTS: Invariable and variable radiographic findings were seen in all four cases of histologically proven Pacman dysplasia. CONCLUSION: Pacman dysplasia presents both constant and variable diagnostic radiographic features.

Shared genetic susceptibility to breast cancer, brain tumors, and Fanconi anemia.

Fanconi anemia is an inherited disease characterized by bone marrow failure, congenital malformations, and predisposition to cancer. The breast cancer susceptibility gene BRCA2 was recently found to be associated with Fanconi anemia complementation group D1 (FA-D1). We examined four kindreds afflicted with Fanconi anemia for the presence of germline BRCA2 mutations. One kindred, of Ashkenazi Jewish ancestry, had five members who were diagnosed with breast cancer and two cousins who were BRCA2*6174delT/C3069X compound heterozygotes and had Fanconi anemia and brain tumors. In another kindred of Ashkenazi Jewish and Lithuanian Catholic ancestry, a child with Fanconi anemia and a medulloblastoma was a BRCA2*6174delT/886delGT compound heterozygote. Two other kindreds each contained a Fanconi anemia-afflicted child who developed medulloblastoma; one child was of Latin American ancestry and a compound heterozygote for BRCA2*I2490T/ 5301insA and the other was African American and a compound heterozygote for BRCA2*Q3066X/E1308X. Median age of the Fanconi anemia-afflicted children at brain tumor diagnosis was 3.5 years. The co-occurrence of brain tumors, Fanconi anemia, and breast cancer observed in one of these kindreds constitutes a new syndromic association. Individuals who carry a germline BRCA2 mutation and who plan to have children with a partner of Ashkenazi Jewish descent should consider undergoing genetic counseling.

Early childhood hearing loss: clinical and molecular genetics. An educational slide set of the American College of Medical Genetics.

An educational slide set entitled "Early Childhood Hearing Loss: Clinical and Molecular Genetics" is offered by the American College of Medical Genetics (ACMG). The slide set is produced in Microsoft PowerPoint 2002. It is extensively illustrated and supported with teaching tools, explanations of each slide and figure, links to Internet resources, and a bibliography. The slide set is expected to be used as a resource for self-directed learning and in support of medical genetics teaching activities. The slide set is available through the ACMG (http://www.acmg.net) for $20, plus applicable tax and shipping. It is the first in a series of educational slide sets to be developed by the ACMG.

Molecular genetic studies of human chromosome 7 in Russell-Silver syndrome.

Russell-Silver syndrome (RSS) is a form of congenital short stature characterized by severe growth retardation and variable dysmorphic features. In some RSS individuals, alterations in imprinted genes may be involved because approximately 7% of sporadic patients have been observed to have maternal uniparental disomy (mUPD) of chromosome 7. RSS patients with structural abnormalities of chromosome 7 have also been described. In these individuals the chromosome rearrangement could disrupt the balance of imprinted genes, contribute to a recessive form of RSS, or lead to haploinsufficiency of a crucial developmental gene product. Because the mechanism and molecular defects on chromosome 7 causing RSS are still unknown, we tested our collection of 77 RSS families for mUPD7 and were able to identify three new cases. We also characterized two RSS patients with de novo cytogenetic abnormalities involving the short arm of chromosome 7. One had a partial duplication [46, XX, dup(7)(p12 p14)] and the second contained a paracentric inversion [46, XY, inv(7)(p14 p21)]. Fluorescence in situ hybridization (FISH) mapping revealed that the breakpoints on 7p14 were localized to the same novel gene, C7orf10, which encompasses >700 kb of DNA. We also identified other transcription units from this immediate region, but all seem to be biallelically expressed when using a somatic cell hybrid assay.