1/3. hypoparathyroidism and facial dysmorphism as main symptoms of 22q.11 deletion syndrome.A 12-year-old Japanese boy with mental retardation and facial dysmorphism developed frequent convulsions, and hypocalcemia due to hypoparathyroidism was recognized. Chromosomal analysis involving the fluorescence in situ hybridization method revealed a microdeletion of 22q11.2. However, other laboratory examinations revealed no cardiac anomaly, thymic hypoplasia, or cleft palate. It is well known that typical cases of 22q11 deletion syndrome have a cardiac anomaly, thymic hypoplasia and a cleft palate. However, the phenotype of 22q11 deletion syndrome is diverse, and hypoparathyroidism and facial dysmorphism have been reported in nine cases, including this case, associated with 22q11 deletion. This combination of clinical manifestations could be given another term, such as hypoparathyroidism-facial syndrome. Some hypoparathyroidism patients due to 22q11.2 deletion may be misdiagnosed as having idiopathic hypoparathyroidism, and a child diagnosed as having hypoparathyroidism should be examined for chromosomal 22q.11.2. deletion.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/3. sex determination of human embryos using the polymerase chain reaction and confirmation by fluorescence in situ hybridization.OBJECTIVE: To use fluorescence in situ hybridization to corroborate the polymerase chain reaction (PCR) preimplantation diagnosis of human embryos in three couples carrying a chromosome X-linked disease. SETTING: Clinical and research IVF laboratories. patients: Individuals undergoing preimplantation diagnosis. RESULTS: Four ETs were performed in couples undergoing preimplantation diagnosis by multiplex PCR or fluorescence in situ hybridization, resulting in the birth of two normal female twins. The result of another is pending. A total of 22 embryos were analyzed by PCR. Embryos that were diagnosed as being at risk of carrying the genetic abnormality (n = 8), embryos that failed diagnosis (n = 4), and genetically normal embryos that arrested development (n = 4) were further analyzed by fluorescence in situ hybridization. The sex of all 16 embryos was determined and confirmed the previous 12 preimplantation diagnoses by multiplex PCR. In addition, fluorescence in situ hybridization analysis allowed the detection of two aneuploid embryos, one XO and one XXY, previously diagnosed by PCR as a normal female and male. Two mosaics were also detected. CONCLUSION: polymerase chain reaction and fluorescence in situ hybridization are possible for preimplantation sex determination in cases of genetic sex-linked disease. fluorescence in situ hybridization, however, supplies additional information about sex chromosome aneuploidy and is not susceptible to contamination or misdiagnosis of monosomy X.- - - - - - - - - - ranking = 10keywords = hybridization (Clic here for more details about this article) |
3/3. Molecular cytogenetics: an essential component of modern prenatal diagnosis.Traditional cytogenetic studies with high-resolution banding techniques have been the mainstay of prenatal diagnosis for > 20 years. However, this approach is limited by the resolution of light microscopy, and it requires cultured cells, necessitating a significant delay in obtaining chromosome studies. The advent of molecular cytogenetics, or fluorescence in situ hybridization, has added an adjunctive tool to overcome both these limitations. During a 16-month period 35 prenatal diagnosis cases had molecular cytogenetic studies performed; 71% of the evaluations were informative. We present five of these cases to illustrate the benefits of this technique for clinical prenatal diagnosis.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |