Know about PCR & antenatal detection of ASD -Possibilities & Future?

Amplification Chart 

III. The C_T value is compared against a standard curve (based on C_T values of control samples and their respective known starting amounts ofDNA or RNA) to determine the amount of DNA or RNA in the patient sample. The presence of a deletion or duplication mutation can be deduced by comparing the amount of DNA or RNA in the patient sample with the amount of DNA or RNA in a control sample. For example, a heterozygous deletion mutation would be indicated if the amount of DNA or RNA in the patient sample were ~50% of the normal control; a duplication mutation would be indicated if the amount of DNA or RNA in the sample were ~150% of the normal control.

 Autism spectrum disorder (ASD) What are the common clinical examples where PCR is of immense value?? Some Clinical Implications

·         While PCR has become a standard technique in all clinical molecular genetics laboratories, quantitative PCR is performed by only a small number of laboratories.

·         FISH Testing  for diseases  A)  Duchenne muscular dystrophy) for hemizygous deletion mutations (e.g., DMD deletions in males affected with  Duchenne muscular dystrophy) can be performed by standard PCR techniques. However, quantitative PCR, rather than standard PCR, must be performed to detect heterozygous deletion mutations (e.g., heterozygous deletions in (1) individuals affected with an autosomal contiguous gene deletion such as Duchenne muscular dystrophy) FISH Testing  for diseases  for diseases B)  . Williams syndrome, (2) carriers of an autosomal recessive disorder such as spinal muscular atrophy, and (3) carriers of an X-linked disorder such as Duchenne muscular dystrophy).

Terms: deletion; duplication; heterozygote; PCR; Targeted mutation analysis

Autism spectrum disorder (ASD) What is meant by 7q11.23 Duplication Syndrome???

Coutsey:-Carolyn B Mervis, PhD, Colleen A Morris, MD, Bonita P Klein-Tasman, PhD, Shelley L Velleman, PhD, and Lucy R Osborne,

FISH Testing  for diseases C)  like 7q11.23 duplication syndrome is characterized by distinctive facial features; cardiovascular disease (dilation of the ascending aorta in 46%); neurologic abnormalities (hypotonia, adventitious movements, and abnormal gait and station); speech sound disorders including motor speech disorders (childhood apraxia of speech and/or dysarthria) and phonologic disorders; behavior problems including anxiety disorders (especially social anxiety disorder [social phobia]), selective mutism, attention deficit hyperactivity disorder (ADHD), oppositional disorders, physical aggression, and autism spectrum disorders (ASD); delayed motor, speech, and social skills in early childhood; and intellectual ability ranging from intellectual disability (~18%) to borderline intellectual ability (~20%) to low average to high average (the remainder). Approximately 30% of individuals with the 7q11.23 duplication have one or morecongenital anomalies.

Diagnosis/testing.

The diagnosis of the 7q11.23 duplication syndrome is established by detection of a recurrent 1.5- to 1.8-Mb heterozygous duplication of the Williams-Beuren syndrome critical region (WBSCR).

Management.

Treatment of manifestations: Aortic dilation is treated with beta blocker therapy and/or surgery as needed. Constipation should be aggressively managed at all ages to prevent encopresis and impaction. Address developmental disabilities, including ASD, through early intervention programs (including speech/language therapy, physical therapy, and occupational therapy), special education programs, and vocational training. Address ASD with applied behavior analytic interventions and other empirically supported psychosocial approaches. Address childhood apraxia of speech (CAS) or manifestations of this disorder with intensive speech/language therapy to maximize effective oral communication and prevent or limit later language impairment and/or reading disorder. Address emotional and behavioral disorders (aggression, social anxiety, selective mutism) with cognitive-behavioral therapy, applied behavior analysis behavior modification intervention, and psychotropic medications as needed.

Surveillance: Routine monitoring of head circumference in infancy. Annual monitoring of aortic diameter (including Zscores in children) and behavior. Annual assessment by occupational and physical therapists and speech and language pathologists until age six years.