A child with unilateral radial aplasia, asymmetry, other malformations, and severe physical and mental retardation is reported. In blood and bone marrow cultures a low mosaicism for trisomy 22 was found. In a few cells a chromosome 22 was missing. The importance of early cytogenetic analysis on large numbers of cells is emphasised, especially in cases of asymmetry where mosaicism is suspected.

A newly formulated mutation selection equilibrium for lethal X linked recessive traits such as Duchenne muscular dystrophy is presented, which allows for both male and female germline mosaicism. Estimates of the additional parameters used are given, thus allowing the incorporation of germline mosaicism into the calculation of genetic risks.

Somatic mosaicism has been implicated as a causative mechanism in a number of genetic and genomic disorders. X-linked acrogigantism (XLAG) syndrome is a recently characterized genomic form of pediatric gigantism due to aggressive pituitary tumors that is caused by submicroscopic chromosome Xq26.3 duplications that include GPR101 We studied XLAG syndrome patients (n= 18) to determine if somatic ...

The majority of children with Dravet syndrome (DS) are caused by de novo SCN1A mutations. To investigate the origin of the mutations, we developed and applied a new method that combined deep amplicon resequencing with a Bayesian model to detect and quantify allelic fractions with improved sensitivity. Of 174 SCN1A mutations in DS probands which were considered "de novo" by Sanger sequencing, we...

Mosaicism involving a normal cell line and an unbalanced autosomal translocation are rare. In this study we present three new cases detected by Single Nucleotide Polymorphism (SNP) array analysis in our routine diagnostic setting. These cases were further characterized using Fluorescence in situ Hybridisation (FISH) analysis and conventional karyotyping. The first case is a mentally retarded ma...

45,X/46,XY mosaicism is a rare sex chromosome disorder of sex development. Short stature is a main feature of boys with this condition. Different causes likely contribute to growth impairment. Growth hormone (GH) has been administered to treat short stature in boys with 45,X/46,XY mosaicism, but conflicting data are available. Here, spontaneous growth patterns as well as short- and long-term fo...

Phylloid hypomelanosis is a distinct type of pigmentary mosaicism characterized by congenital hypochromic macules resembling a floral ornament with various elements such as round or oval patches, asymmetrical macules similar to begonia leaves, or oblong lesions. It has been found to be predominantly associated with abnormalities in chromosome 13 and sometimes as-sociated with different extracut...

von Hippel-Lindau disease (VHL) is an autosomal dominant, familial neoplastic disorder with variable interfamilial and intrafamilial expression. VHL is characterized by pre-disposition to development of a combination of benign and malignant tumours affecting multiple organs. We provide molecular evidence of somatic mosaicism in nearly asymptomatic man whose daughter had VHL. The mosaic subject ...

Two girls with mosaicism for an extra chromosome 9 are reported. Clinical findings included growth and mental retardation, facial dysmorphism, delayed ossification, single flexion crease, gastro-oesophageal reflux in one girl, and ventricular and atrial septal defects in the other patient. These findings are compared to the other previously reported cases of trisomy 9 mosaicism.

Tetraploid-diploid mosaicism in humans is exceedingly rare. We present an 11-year-old boy with tetraploid-diploid mosaicism and coexistent hair hypopigmentation with skin hypo- and hyperpigmentation. This case expands the current literature as we are not aware of previous documentation of this unique combination of pigmentary anomalies.