Genetic 3 Genetic Diseases

What is Trisomy 21 also known as?

Down syndrome.

What extra chromosome is present in Trisomy 21?

An extra copy of chromosome 21.

What are common physical features of Down syndrome?

Up-slanting eyes, epicanthal folds, flat nasal bridge, open mouth with protruding tongue, and hypotonia.

What is the overall risk of having a child with Down syndrome?

1 in 800, with increased risk associated with maternal age.

What cardiovascular issue is associated with Down syndrome?

Cardiac malformations, present in 40-50% of children.

What is a common gastrointestinal malformation associated with Down syndrome?

Duodenal atresia.

What is Hirschsprung disease?

A congenital condition affecting the large intestine, leading to problems with passing stool.

What is the prevalence of intellectual impairment in individuals with Down syndrome?

Near 100%.

What diagnostic tests can estimate the chance of having a baby with Down syndrome?

Maternal screening tests like AFP, Quad screen, and NIPT.

What is the main treatment approach for Down syndrome?

Cardiac evaluation, thyroid hormone screening, auditory screening, dietary counseling, educational intervention, and family support.

What defines Trisomy 18 (Edwards syndrome)?

An extra chromosome 18 causing growth restriction and intellectual disability.

What is a distinctive feature of Trisomy 13 (Patau syndrome)?

Holoprosencephaly and polydactyly.

What causes Turner syndrome?

Presence of only one X chromosome (45,X) in females.

What are some clinical features of Klinefelter syndrome?

Tall stature, small testes, low testosterone, and gynecomastia in males.

What genetic disorder is commonly associated with CGG repeat expansion?

Fragile X syndrome.

What are BRCA1 and BRCA2 associated with?

Increased risk of breast and ovarian cancers.

What is HNPCC also known as?

Lynch syndrome.

What condition is caused by mutations in the APC tumor suppressor gene?

Familial adenomatous polyposis (FAP).

What does the acronym SPROG represent in managing genetic diseases?

Supportive care, Product replacement, Replacement of enzymes, Dietary restriction, Toxic substance removal, Organ transplant, Gene therapy.

Down syndrome (Trisomy 21)

Characterized by an extra copy of chromosome 21; features include flat face, hypotonia, and associated problems like intellectual impairment and cardiac malformations.

Edwards syndrome (Trisomy 18)

Caused by an extra chromosome 18; characterized by growth restriction, clenched hands, heart defects, and severe intellectual disability.

Patau syndrome (Trisomy 13)

Caused by an extra chromosome 13; features include holoprosencephaly and polydactyly.

Turner syndrome

A condition in females caused by a single X chromosome (45,X); features include short stature, infertility, and congenital abnormalities.

Klinefelter syndrome

A male genetic condition caused by an extra X chromosome (47,XXY); features include tall stature, gynecomastia, and infertility.

Fragile X syndrome

An X-linked disorder caused by CGG repeat expansion in the FMR1 gene; leads to intellectual disability and physical features like large ears.

BRCA1 and BRCA2

Tumor suppressor genes; mutations increase the risk of breast, ovarian, and prostate cancers.

Lynch syndrome (HNPCC)

An autosomal dominant disorder that increases the risk of colon and endometrial cancer.

Familial Adenomatous Polyposis (FAP)

An autosomal dominant disorder caused by an APC mutation, leading to hundreds of colon polyps and near 100% colon cancer risk.

Trisomy 21 (Down Syndrome)

Characterized by an extra copy of chromosome 21; features include flat facial profile, up-slanting eyes, hypotonia, single palmar crease, and increased risk for congenital heart defects and intellectual disability.

Trisomy 18 (Edwards Syndrome)

Caused by an extra chromosome 18; clinical features include severe developmental delays, clenched fists with overlapping fingers, heart abnormalities, and rocker-bottom feet.

Trisomy 13 (Patau Syndrome)

Involves an extra chromosome 13; clinical features include severe intellectual disability, holoprosencephaly, polydactyly, cleft lip, and palate.

Turner Syndrome (45,X)

Characterized by the absence of one X chromosome in females; features include short stature, incomplete sexual development, and congenital heart defects like coarctation of the aorta.

Klinefelter Syndrome (47,XXY)

A male disorder caused by an extra X chromosome; features include tall stature, hypogonadism, gynecomastia, and infertility.

Fragile X Syndrome

An X-linked genetic disorder caused by a CGG repeat expansion in the FMR1 gene; it leads to intellectual disabilities, developmental delays, and characteristic physical features such as large ears and a long face.

BRCA1 Gene

A tumor suppressor gene that repairs DNA; mutations increase the risk of breast, ovarian, prostate, and pancreatic cancers.

BRCA2 Gene

Another tumor suppressor gene associated with an increased risk of breast and ovarian cancer, particularly in males for breast cancer.

Hereditary Nonpolyposis Colorectal Cancer (HNPCC)

Also known as Lynch syndrome; caused by mutations in DNA mismatch repair genes, leading to a high risk of colon and endometrial cancers.

Familial Adenomatous Polyposis (FAP)

An autosomal dominant condition caused by APC gene mutations; results in hundreds of colon polyps and nearly 100% risk of colon cancer if untreated.

Management of Genetic Diseases

Includes options such as supportive care, product replacement (e.g., hormonal therapy), enzyme replacement therapy, dietary restrictions, toxic substance removal, organ transplants, and gene therapy.