Wolf-Hirschhorn syndrome due to pure and translocation forms of monosomy 4p16.1 → pter.

The aim of this study was to obtain a quantitative definition of Wolf-Hirschhorn syndrome (WHS) through systematic phenotypic analyses in a group of six children with 4p15.32 → pter, 4p15.33 → pter, or 4p16.1 → pter monosomy (considered together as M4p16.1). These results were used for evaluation of the phenotypic effects of a double chromosome imbalance in one child with 4p16.1 → pter monosomy and additional 11q23.3 → qter trisomy. Children with pure M4p16.1 presented with a total of 227 clinical and morphological traits, of which 119 were positive in at least two of them. These traits overlap to a great extent with clinical criteria defining the WHS phenotype. Among the 103 traits identified in the child with unbalanced translocation der(4)t(4;11)(p16.1;q23.3), most clinical and developmental traits (but only 11 morphological) were found to be shared by WHS children with pure M4p16.1 and at least one reported patient with pure 11q trisomy. Forty-six traits of this child corresponded solely to those identified in at least one child with pure M4p16.1. Only five traits of the hybrid phenotype were present in at least one child with pure distal 11q trisomy but in none of the present children with pure M4p16.1. In conclusion, most of the morphological traits of the hybrid phenotype in the child with der(4)t(4;11)(p16.1;q23.3) can be attributed to the M4p16.1, whereas their overlap with those associated with pure distal 11q trisomy is less evident. Phenotype analyses based on the same systematic data acquisition may be useful in understanding the phenotypic effects of different chromosome regions in complex rearrangements. © 2011 Wiley-Liss, Inc.

The C20orf133 gene is disrupted in a patient with Kabuki syndrome.

Kabuki syndrome (KS) is a rare, congenital mental retardation syndrome. The aetiology of KS remains unknown. Four carefully selected patients with KS were screened for chromosomal imbalances using array comparative genomic hybridisation at 1 Mb resolution. In one patient, a 250 kb de novo microdeletion at 20p12.1 was detected, deleting exon 5 of C20orf133. The function of this gene is unknown. In situ hybridisation with the mouse orthologue of C20orf133 showed expression mainly in brain. The de novo nature of the deletion, the expression data and the fact that C20orf133 carries a macro domain, suggesting a role for the gene in chromatin biology, make the gene a likely candidate to cause the phenotype in this patient with KS. Both the finding of different of chromosomal rearrangements in patients with KS features and the absence of C20orf133 mutations in 19 additional patients with KS suggest that KS is genetically heterogeneous.

The C20orf133 gene is disrupted in a patient with Kabuki syndrome.

BACKGROUND: Kabuki syndrome (KS) is a rare, clinically recognisable, congenital mental retardation syndrome. The aetiology of KS remains unknown. METHODS: Four carefully selected patients with KS were screened for chromosomal imbalances using array comparative genomic hybridisation at 1 Mb resolution. RESULTS: In one patient, a 250 kb de novo microdeletion at 20p12.1 was detected, deleting exon 5 of C20orf133. The function of this gene is unknown. In situ hybridisation with the mouse orthologue of C20orf133 showed expression mainly in brain, but also in kidney, eye, inner ear, ganglia of the peripheral nervous system and lung. CONCLUSION: The de novo nature of the deletion, the expression data and the fact that C20orf133 carries a macro domain, suggesting a role for the gene in chromatin biology, make the gene a likely candidate to cause the phenotype in this patient with KS. Both the finding of different of chromosomal rearrangements in patients with KS features and the absence of C20orf133 mutations in 19 additional patients with KS suggest that KS is genetically heterogeneous.

A dysmorphic boy with 4qter deletion and 4q32.3-34.3 duplication: clinical, cytogenetic, and molecular findings.

An infant boy presented with trigonocephaly, mild craniofacial features, a small VSD, open ductus Botalli (ODB), bilateral hip dysplasia, psychomotor retardation, and hypotonia. The karyotype was 46,XY,del(4)(q34). Unexpectedly, fluorescence in situ hybridization (FISH) studies revealed not only a deletion but also a duplication. The deletion extends from 4qter to 4q34.3 and the duplication from 4q32.3 to q34.3. This is the first description of a deletion inverted duplication 4q. Possible mechanisms we can envision by which this deletion/duplication arose could be a U-type exchange causing end-to-end fusion or a two step event with a paracentric inversion and subsequent cross-over in the inverted segment. This observation suggests that the karyotype of patients with a 4q deletion should be confirmed by molecular cytogenetics.

Lack of effect of polymorphisms in dopamine metabolism related genes on imaging of TRODAT-1 in striatum of asymptomatic volunteers and patients with Parkinson's disease.

SPECT scanning using (99)Tc-TRODAT-1, a ligand that binds to dopamine transporters, may be useful for detection of early Parkinson's disease (PD), diagnosis of presymptomatic individuals, and monitoring disease progression. Understanding whether genetic factors contribute to inter-individual variability is crucial for interpreting imaging results in the context of disease pathophysiology. We tested whether polymorphisms in the genes for catechol-O-methyltransferase (COMT), monoamine-oxidase B (MAO-B), and the dopamine transporter (DAT) influence dopamine uptake parameters in the striatum in vivo in asymptomatic volunteers and patients with PD as measured with (99)Tc-TRODAT-1. (99)Tc-TRODAT-1 binding declined with age in both asymptomatic volunteers and PD patients, and depended on disease duration in PD patients. We found no significant association between COMT, MAO-B, and DAT polymorphisms and results of (99)Tc-TRODAT-1 testing in asymptomatic volunteers or patients with PD. In PD patients, the age of disease onset and speed of progression did not differ based on these polymorphisms. These results demonstrate that these specific genetic variations do not alter the fidelity of (99)Tc-TRODAT-1 as a measure of dopaminergic function in asymptomatic volunteer individuals or patients with PD.