Gene mutation: is a permanent change in the DNA sequence that makes up a gene. Mutations range in size from a single DNA building block (DNA base) to a large segment of a chromosome. Gene mutations occur in two ways: 1. They can be inherited from a parent 2. Acquired during a person’s lifetime.Hereditary Mutations/ Germline Mutations: are passed from parent to child. This type of mutation is presentthroughout a person’s life in virtually every cell in the body. Huntington disease.New (de novo) Mutations: occur only in an egg or sperm cell, or those that occur just after fertilization.An affected child has a mutation in every cell, but has no family history of the disorderAcquired (or somatic) mutations: occur in the DNA of individual cells at some time during a person’s life.environmental factors such as• ultraviolet radiation from the sun• can occur if a mistake is made as DNA copies itself during cell division. Mosaicism: Mutations may also occur in a single cell within an early embryo. As all the cells divide duringgrowth and development, the individual will have some cells with the mutation and some cells without thegenetic change.
Polymorphisms: Eyecolor, hair color, and bloodtype.Although many polymorphisms haveno negative effects on a person’shealth, some of these variations mayinfluence the risk of developingcertain disorders
Gene Mutation (point mutation) • Base substitution • Base insertion • Base deletionChromosome mutation change in chromosome structure• Chromosome deletion• Chromosome duplication• Chromosome inversion• Chromosome translocation change in chromosome number • Non-disjunction
Point MutationDNA ladder mRNA Amino Acid SequenceA T AT A U MetG C GC G CC G C ProT A UG C Transcription G TranslationA T A AspC G CT A UA T A TyrT A UT A UG C GA T A
Point MutationBase Substitution DNA ladder mRNA Amino Acid Sequence A T A T A U Met G C G C G A C U C G C Pro Ser T A U G C Transcription G Translation A T A Asp C G C T A U A T A Tyr T A U T A U G C G A T A
Base Insertion Point MutationBase Deletion DNA ladder mRNA Amino Acid Sequence A T A T A U Met G C G C G C C Pro T G C A U G C Transcription G Translation Asp A T A C G C T A U A T A Tyr T A U T A U G C G A T A
Point MutationDNA ladder mRNA Amino Acid SequenceA T A MetT A UG C GC G C HisC T AT G CG A UA C Transcription G Translation StopC T AT G C AspA A U =Frame ShiftT T AT A U TyrG A UA C G T A
Symptoms of Downs SyndromeVarying Degrees of Mental Retardation- Individuals who have downs syndrome have mentalretardation to varying degrees; some may only have slight learning disabilities, while others mayhave more difficulty.Moon face- This is a medical term for a person who has a large chin and forehead, resulting in amoon shape, when looked at from the side. People with downs syndrome may have thiscondition.Pseduoepicanthic fold- This is a fold of skin of the upper eyelid that partially covers the innercorner of the eye.Larger than normal, sometimes furrowed tongue- This is a tongue marked by numerouslongitudinal grooves on the surface.Larger than normal hand with stubby fingers- An individual with downs syndrome may havebig hands with fat, stubby fingers.Incidence of Downs SyndromeThe incidence of individuals having downs syndrome is 1 out of 800 live births. Children beingborn with downs syndrome are more likely as the age of the mother increases.
Symptoms of Klinefelters Syndrome (XXY)Male Sex Organs- Even when a male is born with XXY sex chromosomes,he still has male sex organs, meaning a penis, testes, etc. However,typically with this syndrome, the sex organs are about half the sex as in anormal male.Absence of Spermatozoa- Usually males with XXY are not able toproduce generative sperm, so they are sterile, meaning they cannotproduce generative sperm to impregnate a woman.Possible Presence of Gynecomastia- Gynecomastia is enlarged breatstsin men. A man with XXY may not have very enlarged breasts but he willstill have larger-than-normal breast tissue than the average normal manhas.Incidence of Klinefelters SyndromeThe incidence of individuals having klinefelters syndrome is 1 out of
Symptoms of Turners SyndromeSexual infantilism- Sexual infantilism refers to a woman havingsexual immaturity, meaning she is not able to develop fullysecondary sexual characteristics, such as enlarged breasts, whichare characteristic and distinguished traits for females.Short Stature- Apart from sexual immaturity, individuals withturners syndrome also have stunted physical growth and normallyhave short stature.Webbing of the Neck- A webbed neck is one in which congenitalskin folds run along the sides of the neck and down to theshoulders. It can be very severe or mild.Incidence of Turners SyndromeThe incidence of individuals having turners syndrome is 1 out of
Symptoms of (Supermale) XYY SyndromeThe only symptoms that may result from beinga supermale (XYY syndrome) are possiblelearning disabilities.Originally, supermales were thought to beextra aggressive, even to the point of beingviolent, but this has since been disproven.Aggressive and violent tendencies do not occurconsistently in supermales for it to be a proventrait.Incidence of SupermalesThe incidence of supermales, or males havingXYY syndrome, is 1 out of 1000 live births.
Symptoms of Pataus SyndromeMicrocephaly (my-kroh-SEHF-uh-lee)- is a neurological condition in which the circumference ofan infants head is significantly smaller than the heads of other people of the same age and sex. Itis a rare condition, but as pataus syndrome is very rare, it correlates.Microphthalmia (my-krahf-THAHL-mee-uh)- is an eye abnormality that arises before birth inwhich one or both eyeballs are abnormally small.BlindnessHeart Defects- which significantly shortens their life. This is one of the reasons why children bornwith this syndrome usually dont live past 2 years of age.Cleft Lip- Cleft lip is a congenital split in the center of the upper lip.Cleft Palate- Cleft palate is a split of the palate, which is the top of the roof of the mouth of anindividual.Incidence of Pataus SyndromeThe incidence of individuals having pataus syndrome is 1 out of 20,000 live births.
Symptoms of Edwards SyndromeSevere heart and kidney defects-In fact, most humans die in the fetal stage whohave this syndrome. And those who do make it past birth do not live long,because of heart and kidney abnormalities.Convex Plantar of Foot- This is a condition in which the sole of a perons foot iscurved. Normally, a healthy human being has a flat foot sole. However, peoplewith edwards syndrome do not; their feet are curved.Abnormal, low set auriculae- An individual with edwards syndrome may havehis/her auriculae, which are the projecting part of the ear lying outside the head,lower than normal on the head. The ear, overall, may look abnormal.Incidence of Edwards SyndromeThe incidence of individuals having edwards syndrome is 1 out of 8,000 livebirths.