Chromosome 5
By Heather Worth
About Chromosome 5
• The average person has two copies of chromosome 5, one from each
parent
• Has 1,700 genes
• Has 181 million base pairs
• Represents almost 6 percent of the total DNA in cells
• One of the largest human chromosomes
• Has one of the lowest gene densities
Cri-du-chat (cat’s cry) Syndrome
• Caused by a deletion at the end of the short (p) arm of chromosome
5
• Not usually inherited
• About ten percent of people with cri-du-chat syndrome inherit it
(recessive allele)
• Estimated in 1 in 20,000 to 50,000 newborns
• Found in people of all ethnic backgrounds
Cri-du-chat Syndrome
• Symptoms: cat-sounding cry, intellectual disability, delayed
development, low birth weight, weak muscle tone, slow growth
• Some are born with a heart defect
• Physical features: small head size, widely set eyes, downward slanted
eyes, low-set ears, small jaw, rounded face, partial fusing in
fingers/toes, single line in the palm of the hand, skin tags in front of
the ear
• No cure, but can go to physical therapy for treatment of some
symptoms
Diastrophic Dysplasia
• Caused by mutations in the SLC26A2 gene
• Inherited (recessive allele)
• Affects about 1 in 100,000 newborns
• Found in all populations, especially Finland
• A type of dwarfism
Diastrophic Dysplasia
• Symptoms: short stature with very short arms and legs, joint
deformities that restrict movement (often make it difficult to walk
and tend to worsen with age), clubfoot, progressive abnormal
curvature of the spine, clubfoot, a cleft palate, swelling of the
external ears which can lead to deformed ears
• Nutritional counseling may be needed, because people with the
disease are usually inactive
Treacher Collins Syndrome
• Caused by mutations in the TCOF1, POLR1C, or POLR1D gene
• Inherited (dominant)
• About 60 percent of these people with the disease get it from new
mutations in the gene
• Found in about 1 in every 50,000 people
• Affects the development of bones and other tissues of the face
Treacher Collins Syndrome
• Symptoms: underdeveloped facial bones, flat cheek bones, and a very
small jaw and chin, cleft palate, defects in the eye, decreased
eyelashes on the lower eyelid, hearing loss, abnormal eye shape
• Some birth defects will be need to be treated with plastic surgery,
help with hearing will also be necessary
Primary Carnitine Deficiency
• Caused by mutations in the SLC22A5 gene
• Inherited (recessive)
• Affects about 1 in 100,000 newborns and 1 in every 40,000 newborns
in Japan
• Prevents the body from using certain fats for energy
Primary Carnitine Deficiency
• Symptoms: severe brain dysfunction, a weakened and enlarged heart,
confusion, vomiting, muscle weakness, and low blood sugar
• Some people don’t show symptoms
• Everyone with this disorder is at risk for heart failure, liver problems,
coma, and sudden death
• It is recommended for people with this disorder to work with a
metabolic doctor and/or dietician
Other Disorders
• Asthma
• Cockayne Syndrome
• Spinal Muscular Atrophy
• Severe Combined Immunodeficiency
• Schizophrenia
• Acute Myelogenous Leukemia
Bibliography
• Background:
https://public.ornl.gov/site/gallery/originals/Chrom05.jpg
• Pictures are hyperlinked
• http://www.news-medical.net/health/What-is-Chromosome-5.aspx
• http://ghr.nlm.nih.gov/condition/cri-du-chat-syndrome
• http://health.nytimes.com/health/guides/disease/cri-du-chatsyndrome/overview.html
• http://ghr.nlm.nih.gov/condition/diastrophic-dysplasia
• http://ghr.nlm.nih.gov/condition/treacher-collins-syndrome
Bibliography
• http://health.nytimes.com/health/guides/disease/treacher-collinssyndrome/overview.html
• http://ghr.nlm.nih.gov/condition/primary-carnitine-deficiency
• http://www.newbornscreening.info/Parents/fattyaciddisorders/Carnit
ine.html
• http://www.ornl.gov/sci/techresources/Human_Genome/project/chr
oanno.shtml