o'toole grace 11100387 bloom syndrome

BLOOM SYNDROME

Presentation by:Grace O’Toole aka:

Bloom–Torre–

Machacek syndrome

History of Bloom

•1st identified by NY dermatologist Dr. David Bloom

•1st identified in 1954

Cause of Bloom• Autosomal recessive gene

characterized by high levels of sister chromatids

• Syndrome problem on chromosome 15

• Cells have genomic instability with excessive homologous recombination

• Increase in chromosome breakage/rearrangement

Cause: BLM gene•Gene encoding protein

RecQL3 helicase

•Mutation of BLM gene inactivate BLM protein’s DNA helicase activity or nullify protein expression

•Lack of BLM leads to increase mutations

Symptoms“Clinical Features”• Short stature

• Rash developing from sun exposure

• High pitched voice

• Facial features: long/narrow face, micrognathism (undersized jaw), prominent nose/ears

• Skin pigmentation change: hypo/hyper-pigment & cafe-au-lait spots (pigmented birthmarks)

• Telangiectasis (dilation of capillaries to appear red) in eyes

Con’t Skin Rash

•Erythematous (reddening), telangiectatic, infiltrated, & scaly

•Appears in butterfly-shaped patch of skin across nose/cheek & back of hands

Con’t Symptoms• Moderate immune deficiency {specifically

immunoglobulin classes} leads to recurrent pneumonia & ear infection

• Hypogonadism (failure to produce sperm) so infertile males

• Premature menopause for women

Complications-Chronic lung problems-Diabetes-Learning disabilities-Small # of mental retardation cases-Susceptibility to cancer

Bloom & Cancer•Elevated rate of mutation brings high risk of cancer

•Leukemia, lymphomas, & carcinomas

•Average age to develop cancer approximately 25 years old

Identification•Confirmed

through lab test: chromosome study

•PCR assay test for chromosome 15

Diagnosis Markers•Drastic

intrauterine growth deficiency with erythematous skin

•Small individual developing cancer

Frequency•Found in larger

quantity in Ashkenazic Jews (carriers 1/100)

•1/50,000 people affected of Central and Easter European Jewish background

Treatment for Identification

•Possible carriers: genetic counseling & genetic testing

•Known carriers: prenatal testing using cytogenetic or molecular methods

Treatment for Cases•No treatment

•Preventative Measures: surveillance for cancer & decreased exposure to sunlight/X-rays

•Possibility: bone marrow transplant

Bioethical Consequences

•Ethical problems to consider:

•Gene testing to be carriers calls into question for risk of child to be affected

•Sibling contempt with smaller sized Bloom Syndrome child compared to child not afflicted

Bibliography•Baxter, Sarah. "BLM Gene

Encodes a RecQ Helicase." Davidson.edu. Davidson College Molecular Biology, n.d. Web. 25 Feb. 2013. <http://www.google.com/imgres?imgurl=http://www.bio.davidson.edu/Courses/Molbio/MolStudents/spring2003/Baxter/BLM.gif>.

•O'Neil, Marla J. "Bloom Syndrome; BLM." Omim. Omim, Oct.-Nov. 2009. Web. 25 Feb. 2013. <http://omim.org/entry/210900>.