CLASS DISCUSSION GENETIC DISEASES

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CLASS DISCUSSION GENETIC
DISEASES Thalassemia Thompson Thompson Case
30 I-Cell Disease Baynes Dominiczak pg.
371 Thompson Thompson pg. 215 Prostate
Cancer Thompson Thompson pg.
318-320 Botchkina GI, et al. Noninvasive
detection of prostate cancer by quantitative
analysis of telomerase activity. Clin Cancer
Res. May 111(9)3243-3249, 2005 (PDF)
Questions are in the notes section below each
slide.
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Thalassemia minor
I
II
III
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History and Physical Findings History
Presentation A child aged 6 months was referred
to a specialist. The child had been born with
dislocated hips and a coarse-featured (Hurler)
face. He had been suffering repeated upper
respiratory tract infections and did not seem to
be developing his motor abilities.
Examination Clinical examination revealed
hyperplasia of the gums, restriction of joint
mobility and hepato-splenomegaly. On listening to
the heart a mitral valve murmur could be
detected. Investigation Further investigation
involved the cell culture of the childs
fibroblasts obtained from a skin biopsy.
Examination of the fibroblasts under the
microscope revealed the presence of numerous
intracellular inclusions which on electron
microscopy were revealed to be large
lysosomes. Biochemical analysis showed decreased
levels of the lysosomal hydrolase
beta-glucuronidase within the fibroblasts, but
elevated levels of this enzyme within the culture
medium.
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Targeting of proteins to lysosomes (I-cell
disease)

• Proteins containing
• mannose-6-phosphate
• are targeted to lysosomes

Asn

• These proteins include the
• lysosomal hydrolases

UDP-

• Phosphate groups are added to
• mannose by transfer of GlcNAc
• phosphate from UDP-GlcNAc

Asn

• Patients with I-cell (for inclusion
• body) disease have a deficiency
• in the enzyme that transfers
• GlcNAc phosphate to mannose
• residues in the Golgi

P

• As a result, the hydrolases cannot
• be targeted to the lysosomes

Asn

• The resulting deficiency in
• lysosomal hydrolases results in
• an accumulation (inclusions)
• of material in the lysosomes

P
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Noninvasive Detection of Prostate Cancer by
Quantitative Analysis of Telomerase Activity G.I.
Botchkina, R.H. Kim, I.L. Botchkina, A.
Kirshenbaum, Z. Frischer, and H.L. Adler Clin
Cancer Res. May 111(9)3243-3249, 2005 Purpose
Prostate cancer is the most common male
malignancy and the second leading cause of male
cancer death therefore, there is urgent
necessity for noninvasive assays for early
detection of prostate cancer. Obtaining prostate
tumor samples surgically is problematic because
the malignancy is heterogeneous and multifocal
and early-stage tumors are nonpalpable. In
contrast, exfoliated cells represent the cancer
status of the entire gland better due to the
general tendency of cancer cells to exfoliate
into biological fluids. The purpose of this study
was to clarify whether quantitative analysis of
telomerase activity in exfoliated cells in urine
could serve as a reliable molecular marker of
prostate malignancy. Experimental Design We
analyzed prospectively post-prostatic examination
exfoliated cells from the urine of 56 patients
undergoing routine prostate screening. Epithelial
cells were isolated and enriched by
immunomagnetic separation. Telomerase activity
was analyzed by quantitative real-time PCR
telomeric-repeat amplification protocol assay
using Opticon MJ research instrument. Results We
report now that all prostate cancer patients
revealed high levels of telomerase activity
thereby showing 100 of the assay sensitivity. In
contrast, the majority of patients with
clinically confirmed benign prostatic hyperplasia
(BPH) did not express any telomerase activity
(70 of all BPH patients), most likely presenting
cancer-free cases, or expressed low levels of
activity (18). However, about 12 of BPH
patients revealed high levels of telomerase
activity that potentially can reflect hidden
prostate cancer. Conclusions We suggest that the
quantitative analysis of telomerase activity can
be useful for the selection of prostate cancer
and cancer-free cases.
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RNA primer
direction of leading strand synthesis
3 5
replication fork
5 3
3 5
End of the chromosome
direction of lagging strand synthesis
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RNA primer
3 5
5 3
3 5
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RNA primer
3 5
5 3
3 5
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RNA primer
3 5
3
3 5

• DNA end synthesized by telomerase
• chromosome gets longer

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RNA primer
3 5
3
3 5

• DNA end synthesized by telomerase
• chromosome gets longer

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Polymerase chain reaction (PCR) analysis
1).
2).
3).
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4).
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TS
SYBR Green
ACX

prime

synthesize


denature and prime



synthesize