1/3. High resolution microarray CGH and MLPA analysis for improved genotype/phenotype evaluation of two childhood genetic disorder cases: ring chromosome 19 and partial duplication 2q.A detailed analysis of the constitutional chromosomal changes in two pediatric patients was performed using high resolution genetic analysis techniques, microarray comparative genomic hybridization (array CGH) and multiplex ligation-dependent probe amplification (MLPA) as well as FISH. The aim was to come to a more precise characterization of the genotype/phenotype relationship. Case 1 was a girl of 25 months, showing areas of hypopigmentation along the lines of Blaschko and no other developmental abnormality. She carried a ring chromosome 19 which we found not to have resulted in loss of subtelomeric sequences, ruling out the possibility that a small subtelomeric loss was causally related to this patient's phenotype. Case 2 was a 9-year-old girl with facial anomalies and mild growth and mental retardation carrying an unidentified addition on chromosome 2p. We found that the addition was duplicated 2q35-q37.3 and that the addition was not accompanied by loss of 2pter or any other chromosomal region. Together with literature data, we hypothesize that pediatric patients with 'pure' trisomy 2q including bands 2q35-q37.1 may have a moderate clinical phenotype as opposed to patients with duplications proximal to 2q33 or patients with duplications 2q3 with accompanying distal deletion. These two examples illustrate the additional value of new, high resolution genetic analysis techniques for a better characterization of the genotype/phenotype relationship in childhood chromosomal disorders.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/3. Pallister-Killian syndrome: a mild case diagnosed by fluorescence in situ hybridization. review of the literature and expansion of the phenotype.Pallister-Killian syndrome (PKS) is a rare disorder characterized by a specific combination of anomalies, mental retardation and mosaic presence of a supernumerary isochromosome 12p which is tissue-limited. We report an atypical case of PKS with a mild phenotype. Flourescence in situ hybridization (FISH) was used to demonstrate that the supernumerary marker chromosome identified in the patient's fibroblasts was an isochromosome 12p. This study broadens the spectrum of PKS phenotype. It also illustrates the usefulness of fluorescence in situ hybridization in diagnosis of patients with chromosomal abnormalities and mild or atypical clinical findings.- - - - - - - - - - ranking = 6keywords = hybridization (Clic here for more details about this article) |
3/3. Phylloid pigmentary pattern with mosaic trisomy 13.In most patients with hypomelanosis of Ito, the hypopigmentation is characterized by narrow bands following the lines of Blaschko. We report a 13-year-old severely retarded girl with leaf-shaped patches of hypopigmentation on the back together with short stature, scoliosis, facial dysmorphism, and asymmetrical leg length. The cytogenetic examination of both lymphocytes and fibroblasts demonstrated a mosaicism of 46,XX/47,XX 13. This result was confirmed by in situ hybridization using a chromosome 13-specific library in interphase cells. The pigmentary disturbance of our patient was similar to the phylloid pattern (type 3) of the classification of pigmentary patterns postulated by Happle. This type has been described in four patients so far, along with additional anomalies and a chromosomal mosaisicm in two patients.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |