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Genetic Disorders. Fragile-X Syndrome (FXS) Prevalence Approximately 1 in 5000 births 1 in 4000 for males, 1 in 6000 for females Why? In many X linked conditions only males who inherit the abnormal gene are affected (e.g. red-green colour blindness).
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Genetic Disorders • Fragile-X Syndrome (FXS) • Prevalence • Approximately 1 in 5000 births • 1 in 4000 for males, 1 in 6000 for females • Why? • In many X linked conditions only males who inherit the abnormal gene are affected (e.g. red-green colour blindness). • Fragile X syndrome is an exception, in that females can also be affected – but prevalence is lower and symptoms are less severe.
Premutation versus Full Mutation • “Normal” Persons • A section of the DNA in the FMR1 gene (X chromosome) repeats about 30 times. • Sequence: cytosine, guanine and guanine (CGG). • Persons with Premutation • CGG repeats 55-200 times. • Persons with Full Mutation • CGG repeats 200-800 times.
38 weeks 4 pounds, 13 ounces
More than two standard deviations below expected birth weight for gestation time for preterm and full term babies. Public Health Agency of Canada: http://www.phac-aspc.gc.ca/rhs-ssg/bwga-pnag/index-eng.php Can include: Low birth weight (LBW) < 5.5 pounds Very low birth weight (VLBW) < 3.3 pounds Extremely low birth weight (ELBW) < 1.1 pounds Small for Gestational Age
Appropriate Less than 2 standard deviations below expected birth weight for gestation time. Smaller than 90th percentile of expected birth weight for gestational time. Can include: Low birth weight (LBW) < 5.5 pounds Very low birth weight (VLBW) < 3.3 pounds Extremely low birth weight (ELBW) < 1.1 pounds Appropriate for Gestational Age (AGA)