High resolution prometaphase chromosome banding has allowed the detection of discrete chromosome aberrations which escaped earlier metaphase examinations. Consistent tiny deletions have been detected in some well established malformation syndromes: an interstitial deletion in 15q11/12 in the majority of patients with the Prader-Willi syndrome and in a minority of patients with the Angelman (hap...

We report on a male patient with severe autistic disorder, lack of oral language, and dysmorphic features who carries a rare interstitial microdeletion of 4.96 Mb at chromosome 6q14.1-q15. The patient also harbors a maternally inherited copy number gain of 1.69 Mb at chromosome Xp22.31, whose pathogenicity is under debate.

Since 1995, thanks to a large number of studies, Y chromosome microdeletion screening has become part of the routine diagnostic work-up of severe male factor infertility. Many initial contradictory issues such as variability in deletion frequency, markers to be tested, presence of deletions in 'fertile' men, and genotype-phenotype correlation has been resolved. Past and present unresolved issue...

We report monozygotic twins concordant for 22q11.2 deletion but discordant for clinical phenotype. Both boys show the typical dysmorphic features with short palpebral fissures, square nasal tip, small mouth, and both have nasal speech, but only one twin had a heart defect. They show that the phenotypic variability seen in this microdeletion syndrome cannot be explained on the basis of genotypic...

We describe a boy presenting with intellectual disability and dysmorphic features in whom a cryptic microdeletion in chromosome band 2q12.1 was identified with array CGH. The deletion results in a loss of the POU3F3 and MRPS9 genes. In this paper, we discuss the possible role of POU3F3 haploinsufficiency in relation to the boy's phenotype.

The DiGeorge Syndrome results from microdeletion in a small segment of the chromosome 22. When inherited from parents, it follows autosomal dominant patterns. There are variable clinical features related to the DiGeorge Syndrome. The most common ones are congenital heart diseases, thymic hypoplasia, learning difficulties, characteristic facial appearance, hypocalcaemia, and psychotic disorders ...

A new case of a de novo 3q26.33q27.3 microdeletion is reported. The fetus had a sonographically undiagnosable polymalformative syndrome. The case highlights the difficulties of echographic diagnosis of such syndromes and leads to reflection on the difficulties of appropriate counselling in cases of uncertainty.

We present a male patient with constitutional ring 1 chromosome and subsequent 6 Mb deletion at 1q43q44. The patient displays overlapping clinical features with reported patients with ring 1 chromosome and 1q43q44 microdeletion syndrome. To our knowledge, this is the first patient with ring 1 chromosome characterized by comparative genomic hybridization.

We report the first microdeletion (26 kb) of the biotinidase gene (BTD) that involves three of the four exons of the gene. This deletion further exemplifies the importance of performing microarray analysis or other methodologies for a deletion of the BTD gene when the enzymatic activity indicates lower activity than can be attributed to the mutations identified by DNA sequencing.