Diagnoses - Part 3 of 4 Flashcards
What is part of routine workup of child with mental retardation but without dysmorphic features or neurological findings?
CHROMOSOMAL ANALYSIS
Pattern of inheritance in Wilson’s disease
AUTOSOMAL RECESSIVE
Pattern of inheritance in Huntington’s disease
AUTOSOMAL DOMINANT
Polymerase chain reaction (PCR) used in genetic linkage studies involves:
AMPLIFICATION OF MICROSATELLITE MARKERS
What conditions associated w MR have an autosomal recessive inheritance pattern?
ADRENOGENITAL SYNDROME, HURLER’S, TAY- SACHS, PHENYLKETONURIA
4 y/o does not run/climb, falls, has iliopsoas/quadriceps/gluteal weakness, enlargement of calves with firm, “rubbery” consistency, decreased DTRs and normal sensation. Wide based stance and walks waddling. When rising from the ground, uses a four-point position through full extension of all four extremities. Has family h/o similar sx in males. 1) EMG reveals? 2) Genetic mutation in what protein?
1) SMALL, SHORT-LASTING MOTOR UNIT POTENTIALS WITH INCREASED RECRUITMENT 2) DYSTROPHIN
14 y/o girl presents with delayed onset of puberty, short status, and a history of cardiac abnormalities and hypertension. She has poor social skills. Psychological assessment reveals a normal verbal IQ and a below-normal performance IQ. Which of the following is the most likely dx?
TURNER SYNDROME
The Sural nerve biopsy of a pt w charcot-marie-tooth type 1 is shown (image), exam shows diminished LE DTRs and deformities of feet BL. These deformities are typical of which molecular abnormality?
DUPLICATION OF THE PERIPHERAL MYELIN PROTEIN GENE
Increase risk for psychopathology in offspring?
HAVING BIO-RELATIVES WITH PSYCHIATRIC ILLNESS
15 y/o pt w/ hx of atypical seizures that include psychomotor attacks and generalized motor episodes. Pt does poorly in school. Exam reveals skin lesion, no other abnormalities. A mutation of which gene?
TSC-1 (TUBEROUS SCLEROSIS GENE 1)
Epigenetic change with fragile X mental retardation 1 gene in fragile x syndrome?
METHYLATION OF THE CPG SITES OF THE PROMOTER REGION
What are splice variants?
DIFFERENT PROTEINS ENCODED BY THE SAME GENE
Which of the following occurs in epigenetic histone protein amino acid residue modification: There is little or no effect on chromatin remodeling, Acetylation is generally rapid and reversible, there is an increase in the positive charge on histones, there is an increase in the interaction with phosphates of the DNA, DNA methylation predominantly activated gene transcription
Acetylation is generally rapid and reversible
Genetic method for analysis of rare variations?
NEXT GENERATION SEQUENCING
Where are DNA methylation regulatory enzymes and proteins found?
MITOCHONDRIA
Small insertions and deletions in DNA sequence referred to as
INDELS
The most serious limitation of the candidate gene approach in identifying genetic disorder
HIGH PROBABILITY OF FALSE POSITIVE FINDINGS
Genetic mechanism in velocardiofacial syndrome
GENETIC DELETION
A young girl has developmental regression, loss of motor and language, stereotyped hand movements, muscle hypotonia, autonomic dysfunctions, and severe cognitive impairment. What genes are involved?
MECP2 CODING FOR METHYL CPG-BINDING PROTEIN 2
what genetic mechanism accounts for schizophrenia, autism, intellectual disability despite association with decreased facility?
DE NOVO MUTATIONS
This involves genetic control by factors other than DNA sequence
EPIGENETICS
Proportion of the genome composed of the “exome”
2%
What CYP450 polymorphism can lead to lower than expected lower than normal risperidone blood levels?
MULTIPLE COPIES OF WILD-TYPE ALLELES
Genetic copy number variations in individuals with severe neurodevelopmental disorders display what difference when compared to controls?
INCREASE IN BURDEN OF CNVS