It was also able to detect smaller atypical deletions that are easily missed using FISH. These factors, along with the lower expense and easier testing mean that this MLPA probe could replace FISH in clinical testing.Genetic testing using BACs-on-Beads has been successful in detecting deletions consistent with 22q11.2DS during prenatal testing. Array-comparative genomic hybridization (array-CGH) uses a large number of probes embossed in a chip to screen the entire genome for deletions or duplications. It can be used in post and pre-natal diagnosis of 22q11.2.Fewer than 5% of individuals with symptoms of DiGeorge syndrome have normal routine cytogenetic studies and negative FISH testing. In these cases, atypical deletions are the cause. Some cases of 22q11.2 deletion syndrome have defects in other chromosomes, notably a deletion in chromosome region 10p14. Treatment
No cure is known for DiGeorge syndrome. Certain individual features are treatable using standard treatments. The key is to identify each of the associated features and manage each using the best available treatments.For example, in children, it is important that the immune problems are identified early, as special precautions are required regarding blood transfusion and immunization with live vaccines. Thymus transplantation can be used to address absence of the thymus in the rare, so-called "complete" DiGeorge syndrome. Bacterial infections are treated with antibiotics. Cardiac surgery is often required for congenital heart abnormalities. Hypoparathyroidism causing hypocalcaemia often requires lifelong vitamin D and calcium supplements.
A computed tomography scan or MRI scan can also be used for more detailed imaging. Finally, the diagnosis of Wilms tumor is confirmed by a tissue sample. In most cases, a biopsy is not done first because there is a risk of cancer cells spreading during the procedure. Treatment in North America is nephrectomy or in Europe chemotherapy followed by nephrectomy. A definitive diagnosis is obtained by pathological examination of the nephrectomy specimen. Staging
Staging is a standard way to describe the extent of spread of Wilms tumors and to determine prognosis and treatments. Staging is based on anatomical findings and tumor cells pathology. According to the extent of tumor tissue at the time of initial diagnosis, five stages are considered.In Stage I Wilms tumor (43% of cases), all of the following criteria must be met:
Tumor is limited to the kidney and is completely excised. The surface of the renal capsule is intact. The tumor is not ruptured or biopsied (open or needle) prior to removal. No involvement of extrarenal or renal sinus lymph-vascular spaces
No residual tumor apparent beyond the margins of excision. Metastasis of tumor to lymph nodes not identified.In Stage II (23% of cases), 1 or more of the following criteria must be met:
Tumor extends beyond the kidney but is completely excised. No residual tumor apparent at or beyond the margins of excision. Any of the following conditions may also exist:
Tumor involvement of the blood vessels of the renal sinus and/or outside the renal parenchyma.