Genetic Disorders

These flashcards cover important genetic terminology, inheritance patterns, syndromes, and chromosomal abnormalities to assist in exam preparation.

What is the difference between a 'Sequence' and an 'Association' in genetic terminology?

Sequence is a recognizable pattern of multiple anomalies from a single problem of morphogenesis; Association is a pattern of malformations occurring too frequently together without known etiology.

What are the key characteristics of Autosomal Dominant inheritance?

Affected individuals occur in every generation; examples include Marfan’s syndrome and Huntington’s disease.

What are the key characteristics of Autosomal Recessive inheritance?

Often skips generations; usually has unaffected carriers as parents; examples include Cystic Fibrosis and PKU.

What characterizes X-linked Recessive inheritance?

Typically only males are affected; females are often carriers. Examples include Hemophilia and Duchenne Muscular Dystrophy.

Define Hypertelorism.

Increased distance between the orbits (eyes).

Define Micrognathia.

Abnormally small mouth or jaw.

Define Synophrys.

'Unibrow' (confluent eyebrows).

Define Philtrum.

Vertical indentation in the middle of the upper lip.

Define Coloboma.

Missing piece of tissue in the eye.

Define Camptodactyly.

Permanently bent fingers or toes.

What are the primary risk factors for Trisomy 21 (Down Syndrome)?

Advanced maternal age (>35 years) and low maternal serum alpha-fetoprotein.

What are the clinical features of Trisomy 21 (Down Syndrome)?

Moderate intellectual disability, hypotonia, short stature, increased risk for leukemia, Hirshsprung disease, and congenital heart defects.

What distinct physical features characterize Down Syndrome?

Simian crease, Brushfield spots, macroglossia, flat facial profile, and up-slanted palpebral fissures.

What is the prognosis of Trisomy 13 (Patau Syndrome)?

Very poor; about 80% die within 1 month.

What features are associated with Trisomy 13 (Patau Syndrome)?

Severe intellectual disability, holoprosencephaly, cleft lip/palate, polydactyly, and punched-out scalp lesions.

What are the hallmark physical features of Trisomy 18 (Edwards Syndrome)?

Rocker bottom feet, clenched hands with overlapping fingers, prominent occiput, micrognathia, and low birth weight.

What is the genetic cause of Turner Syndrome?

Absence of an X chromosome (45,X); usually paternally derived loss.

What are the most common physical traits of Turner Syndrome?

Short stature, webbed neck, shield chest (wide-set nipples), coarctation of the aorta.

What is the treatment focus for Turner Syndrome?

Hormone therapy and growth hormone replacement.

What are the features of Klinefelter Syndrome (47,XXY)?

Tall/slim male phenotype, gynecomastia, hypogonadism, infertility, and incomplete virilization.

What causes Fragile X Syndrome?

CGG trinucleotide repeat on the X chromosome.

How does Fragile X Syndrome present?

Intellectual disability, long face with prominent jaw, large ears, and testicular enlargement.

What is Alport Syndrome?

An X-linked disorder affecting the basement membrane, leading to glomerulonephritis, hearing loss, and ocular defects.

Differentiate between Prader-Willi and Angelman Syndrome.

Prader-Willi: paternal deletion leading to failure to thrive, hyperphagia. Angelman: maternal deletion leading to severe intellectual disability and 'happy puppet' presentation.

What are the overgrowth features of Beckwith-Wiedemann Syndrome?

Macrosomia, macroglossia, omphalocele, hemihyperplasia.

What is the genetic cause of Marfan Syndrome?

Fibrillin 1 gene (FBN1) mutation.

What body systems are affected in Marfan Syndrome?

Skeletal, ocular, cardiac.

What are the features of Ehlers-Danlos Syndrome (Classic Type)?

Skin hyperextensibility, joint hypermobility, fragile skin with 'cigarette paper' scarring.

What is the triad of symptoms for Osteogenesis Imperfecta (Type I)?

Frequent fractures, blue sclera, and hearing loss.

What are the features of Smith-Lemli-Opitz Syndrome?

Microcephaly, syndactyly of the second and third toes, ambiguous genitalia.

Describe the clinical progression of Hurler Syndrome.

Normal growth initially, then developmental delay peaking at 2-4 years, with coarse facial features and clawed hands.

What does the mnemonic CHARGE stand for?

Coloboma, Heart defects, Atresia of choanae, Retarded growth/development, Genital hypoplasia, Ear anomalies.

What does the VACTERL association include?

Vertebral defects, Anal atresia, Cardiac defects, Tracheo-Esophageal fistula, Renal anomalies, Limb abnormalities.

What are the features of Cornelia de Lange Syndrome?

Synophrys, long curly eyelashes, small upturned nose, thin lips, upper extremity defects.

How does Noonan Syndrome present?

Short stature, webbed neck, pulmonary stenosis, low-set ears; often referred to as 'Male Turner Syndrome'.

What are the facial features of Fetal Alcohol Syndrome?

Smooth philtrum, thin upper lip, short palpebral fissures, microcephaly.

What is the hallmark sign of Cri du Chat syndrome?

A high-pitched, monochromatic 'cat-like' cry in newborns.

What is the

CATCH 22 mnemonic? Cardiac defects, Abnormal facies, Thymic aplasia, Cleft palate, Hypocalcemia, 22q deletion.

What are the unique personality traits of Williams Syndrome?

Highly social 'cocktail party' personality, broad forehead, full lips, and supravalvular aortic stenosis.

What is the genetic cause of Crouzon Syndrome?

Craniosynostosis leading to proptosis and beaked nose.

What are the clinical features of Treacher Collins syndrome?

Mandibulofacial dysostosis, malar hypoplasia, down-slanting eyes, small jaw.

What constitutes the Pierre Robin Sequence?

Micrognathia, Glossoptosis, Airway obstruction, and Cleft Palate.

When should you suspect an Inborn Error of Metabolism in an infant?

When an infant presents with 'sepsis-like' symptoms and no evidence of infection, particularly after feeding.

What is the classic sign of Phenylketonuria (PKU)?

Musty or 'mousy' odor to urine or sweat.

What is the dietary management for PKU?

Lifelong low phenylalanine diet, avoiding protein and aspartame.

What is Galactosemia?

Deficiency of GALT enzyme presenting with cataracts, hepatomegaly, associated with E. coli sepsis.

What signs indicate Congenital Adrenal Hyperplasia (CAH)?

Virilization in females, salt-wasting crisis with hyponatremia and hyperkalemia.

Match the Glycogen Storage Disease to its buzzword: Von Gierke.

Doll-like face, lactic acidosis, hypoglycemia.

Match the Glycogen Storage Disease to its buzzword: Pompe.

Cardiomyopathy, hypotonia (floppy baby).

Match the Glycogen Storage Disease to its buzzword: McArdle.

Exercise intolerance, muscle cramping (no hypoglycemia).

Differentiate Tay-Sachs from Niemann-Pick diseases.

Both present with 'Cherry Red Spot' and neurodegeneration; Niemann-Pick has hepatosplenomegaly.

What is the classic presentation of Tay-Sachs disease?

Cherry-red spot on the macula, neurodegeneration without hepatosplenomegaly.

What is an example of an X-linked disorder leading to hearing loss?

Alport Syndrome.

What is a common feature in neurodegenerative lipid storage disorders?

Cherry-red spot on the macula.

What is the risk for patients with Beckwith-Wiedemann Syndrome?

Increased risk for Wilms tumor.

What is a significant facial characteristic in patients with Fragile X Syndrome?

Long face with prominent jaw.

In Klinefelter syndrome, what gene is typically mutated leading to the condition?

No specific gene mutation; characterized by an extra X chromosome.

What are common features of Duchenne Muscular Dystrophy?

Muscle wasting, weakness, pseudohypertrophy of calves.

What inheritance pattern does Cystic Fibrosis follow?

Autosomal Recessive.

What syndrome is characterized by tall stature and arachnodactyly?

Marfan Syndrome.

What is the condition resulting from a defect in collagen synthesis leading to stretchy skin?

Ehlers-Danlos Syndrome.

What are the common facial features of Fetal Alcohol Syndrome?

Smooth philtrum, thin upper lip, microcephaly.

What condition leads to excessive growth due to unregulated cell division?

Beckwith-Wiedemann Syndrome.

What is an important diagnostic tool for detecting Chromosomal Abnormalities?

Karyotyping.

Which chromosome is affected in Down syndrome?

Chromosome 21.

What screening test can indicate the risk of Trisomy 21 during pregnancy?

Maternal serum alpha-fetoprotein test.

What genetic condition is characterized by a single palmar crease?

Down syndrome.

How do you treat Women with Turner syndrome to aid in secondary sexual characteristics?

Hormone replacement therapy.

What condition is associated with holoprosencephaly?

Trisomy 13 (Patau Syndrome).

What mutation leads to the symptoms of Fragile X Syndrome?

CGG triplet repeat expansion.

What is U-shaped palpebral fissures associated with?

Fetal Alcohol Syndrome.

What are the typical symptoms of Osteogenesis Imperfecta?

Brittle bones, blue sclera, and recurrent fractures.

What genetic inheritance pattern is seen in Huntington's disease?

Autosomal dominant.

What does the acronym 'CHARGE' represent in genetics?

Coloboma, Heart defects, Atresia of choanae, Retarded growth, Genital hypoplasia, Ear anomalies.

What does Beckwith-Wiedemann Syndrome increase the risk for?

Wilms tumor and adrenal tumors.

What type of collagen is affected in Ehlers-Danlos Syndrome?

Type III collagen.

What is a key indicator of Smith-Lemli-Opitz Syndrome?

Defect in cholesterol biosynthesis.

What is a defining characteristic of Turner Syndrome?

Short stature and absence of an X chromosome.

What syndrome presents with a 'happy puppet' demeanor?

Angelman Syndrome.

What should be monitored in children with Klinefelter syndrome?

Testosterone levels and potential development of breast tissue.

How does Marfan Syndrome affect the eyes?

Causes ectopia lentis (dislocated lens).

Which condition is commonly compared to Turner Syndrome in males?

Noonan Syndrome.

What does the term 'hypotonia' refer to in genetics?

Decreased muscle tone.

What is the clinical presentation of Alport Syndrome?

Nephritis, hearing loss, and eye defects.

What is a common feature of VACTERL association?

Multiple congenital anomalies affecting various organ systems.

What are common prenatal indicators of genetic disorders?

Ultrasound findings like anomalies in structures.

What are characteristics of Cri du Chat syndrome?

High-pitched cry, intellectual disability, and distinct facial features.

Which syndrome is characterized by upper extremity defects and distinct facial features?

Cornelia de Lange syndrome.

What is the significance of the 22q11 deletion?

It causes DiGeorge syndrome and velocardiofacial syndrome.

What is the outcome of infants with Trisomy 18?

Poor prognosis and many die within the first year.

What are the common clinical features of Edwards syndrome?

Rocker bottom feet, clenched hands, and micrognathia.

What type of anemia may result from Alport Syndrome?

Anemia can occur due to chronic kidney disease.

What is the purpose of genetic counseling?

To provide information and support to families at risk for genetic disorders.

What are some features of Fragile X Syndrome in males?

Intellectual disability, large ears, and hyperactivity.

What is the relationship between maternal age and genetic abnormalities?

Advanced maternal age increases the risk of chromosomal abnormalities.

What are the classical symptoms of PKU?

Musty odor, intellectual disability, and eczema.

What can result from untreated congenital adrenal hyperplasia?

Adrenal crisis and electrolyte imbalances.

Which syndrome can cause excessive appetite and obesity from a neonatal state?

Prader-Willi Syndrome.

What is a classic symptom of Galactosemia?

Cataracts in newborns.

How is polysaccharide metabolism affected in glycogen storage diseases?

Disruption in glycogen breakdown leading to storage problems.