Genetic disorders

Genetic disorders US Medical PG Question 1: A 25-year-old man with a genetic disorder presents for genetic counseling because he is concerned about the risk that any children he has will have the same disease as himself. Specifically, since childhood he has had difficulty breathing requiring bronchodilators, inhaled corticosteroids, and chest physiotherapy. He has also had diarrhea and malabsorption requiring enzyme replacement therapy. If his wife comes from a population where 1 in 10,000 people are affected by this same disorder, which of the following best represents the likelihood a child would be affected as well?

• A. 0.01%
• B. 2%
• C. 0.5%
• D. 1% (Correct Answer)
• E. 50%

Genetic disorders Explanation: ***Correct Option: 1%*** - The patient's symptoms (difficulty breathing requiring bronchodilators, inhaled corticosteroids, and chest physiotherapy; diarrhea and malabsorption requiring enzyme replacement therapy) are classic for **cystic fibrosis (CF)**, an **autosomal recessive disorder**. - For an autosomal recessive disorder with a prevalence of 1 in 10,000 in the general population, **q² = 1/10,000**, so **q = 1/100 = 0.01**. The carrier frequency **(2pq)** is approximately **2q = 2 × (1/100) = 1/50 = 0.02**. - The affected man is **homozygous recessive (aa)** and will always pass on the recessive allele. His wife has a **1/50 chance of being a carrier (Aa)**. If she is a carrier, she has a **1/2 chance of passing on the recessive allele**. - Therefore, the probability of an affected child = **(Probability wife is a carrier) × (Probability wife passes recessive allele) = 1/50 × 1/2 = 1/100 = 1%**. *Incorrect Option: 0.01%* - This percentage is too low and does not correctly account for the carrier frequency in the population and the probability of transmission from a carrier mother. *Incorrect Option: 2%* - This represents approximately the carrier frequency (1/50 ≈ 2%), but does not account for the additional 1/2 probability that a carrier mother would pass on the recessive allele. *Incorrect Option: 0.5%* - This value would be correct if the carrier frequency were 1/100 instead of 1/50, which does not match the given population prevalence. *Incorrect Option: 50%* - **50%** would be the risk if both parents were carriers of an autosomal recessive disorder (1/4 chance = 25% for affected, but if we know one parent passes the allele, conditional probability changes). More accurately, 50% would apply if the disorder were **autosomal dominant** with one affected parent, which is not the case here.

Genetic disorders US Medical PG Question 2: A 23-year-old woman and her husband come to a genetic counselor because she is concerned about the chance of having an inherited defect if they had a child. Family history reveals no significant family history in her husband; however, her sister had a son who has seizures, failure to thrive, and neurodegeneration. She does not remember the name of the disease but remembers that her nephew had sparse, brittle hair that kinked in odd directions. She does not think that any other members of her family including her sister's husband have had this disorder. If this couple had a son, what is the most likely chance that he would have the same disorder that affected the patient's nephew?

• A. 100%
• B. 12.5%
• C. 25% (Correct Answer)
• D. 50%
• E. Close to 0%

Genetic disorders Explanation: ***25%*** - The nephew's symptoms of **seizures, failure to thrive, neurodegeneration**, and **sparse, brittle, kinky hair** are highly indicative of **Menkes disease**, an **X-linked recessive** disorder. - Since the patient's sister had an affected son, the sister is an **obligate carrier** of the mutation. - The patient and her sister share the same parents, so their mother must be a carrier (or have the mutation). - The patient herself has a **50% chance of being a carrier**. - **If the patient is a carrier**, each son has a **50% chance** of being affected. - **Overall probability**: 0.5 (chance patient is carrier) × 0.5 (chance son inherits mutation) = **0.25 = 25%**. *Close to 0%* - This would only be correct if the patient had no chance of being a carrier, which is not the case given her family history. - Her sister's affected son confirms the mutation is present in the maternal lineage. *100%* - This would only occur if the patient were definitely a carrier AND all male offspring inherited the mutation, or if the disorder were autosomal dominant with complete penetrance. - For **X-linked recessive** disorders, even carrier mothers only pass the mutation to 50% of sons on average. *12.5%* - This percentage might represent additional generational steps or compound probabilities not relevant to this direct parent-child scenario. - The correct calculation for this scenario is 50% × 50% = 25%. *50%* - This would be correct if we knew with certainty that the patient is a carrier. - However, since we only know her sister is a carrier, the patient has a 50% chance of being a carrier herself, making the overall risk 25%. - This is a common error in genetic counseling calculations—forgetting to account for the uncertain carrier status of the at-risk individual.

Genetic disorders US Medical PG Question 3: A 30-year-old man is brought into the emergency room for complaints of acute onset chest pain and shortness of breath. He has a history of mental retardation and lives at home with his adoptive parents. His parents inform you that he has not seen a doctor since he was adopted as child and that he currently takes no medications. The patient's temperature is 99.1°F (37.3°C), pulse is 108/min, blood pressure is 125/70 mmHg, respirations are 25/min, and oxygen saturation is 92% on 2L nasal cannula. Physical exam is notable for a tall, thin individual with high-arched feet and mild pectus excavatum. There is mild asymmetry in the lower extremities with discomfort to dorsiflexion of the larger leg. Lung auscultation reveals no abnormalities. What is the most appropriate next step in management?

• A. Chest radiograph
• B. Serum blood test
• C. Genetic testing
• D. Angiogram
• E. Electrocardiogram (Correct Answer)

Genetic disorders Explanation: ***Correct: Electrocardiogram*** - **Acute chest pain** mandates an immediate **ECG** as the first diagnostic test to rule out **ST-elevation myocardial infarction (STEMI)**, which requires emergent intervention (PCI or thrombolysis). - While this patient's presentation is highly suspicious for **pulmonary embolism (PE)** given the **unilateral leg swelling with pain on dorsiflexion** (suggestive of DVT), **tachycardia**, **tachypnea**, and **hypoxemia**, the ECG remains the most appropriate initial step per ACLS protocols for chest pain. - ECG can also show findings suggestive of PE (sinus tachycardia, S1Q3T3 pattern, right heart strain) and help differentiate cardiac from pulmonary etiologies. - The **Marfanoid features** (tall, thin, pectus excavatum, high-arched feet) raise concern for **aortic dissection**, which ECG can help evaluate alongside clinical assessment. *Incorrect: Chest radiograph* - Chest X-ray is critical in the workup and would typically be ordered simultaneously with or immediately after ECG in this patient with suspected PE. - CXR helps exclude pneumothorax, pneumonia, and can show classic PE findings (Westermark sign, Hampton's hump), though it is often normal in PE. - In the context of Marfan syndrome, CXR can reveal a widened mediastinum suggesting aortic dissection. - However, ECG takes precedence as the immediate first step for any acute chest pain presentation. *Incorrect: Serum blood test* - Laboratory tests including **cardiac troponins** (for MI), **D-dimer** (for PE), and **CBC** are important but take time to result. - D-dimer would be useful in this moderate-to-high probability PE case, but imaging (CT pulmonary angiography) would be more appropriate given the high clinical suspicion. - Blood tests do not provide the immediate actionable information needed as the first diagnostic step in acute chest pain. *Incorrect: Genetic testing* - While the patient's phenotype suggests **Marfan syndrome** or another connective tissue disorder, genetic testing is an outpatient diagnostic tool for long-term management. - It provides no immediate utility in the acute management of chest pain and respiratory distress. - Genetic counseling and testing would be appropriate after stabilization and initial workup. *Incorrect: Angiogram* - **CT pulmonary angiography** would be the definitive test for PE diagnosis after initial ECG and CXR, but is not the immediate first step. - **Cardiac catheterization** would be indicated if ECG showed STEMI or if there was high suspicion for ACS after initial workup. - **CT aortography** might be needed if aortic dissection is suspected based on initial findings. - Angiography is an invasive or advanced imaging procedure performed after non-invasive screening tests guide the diagnosis.

Genetic disorders US Medical PG Question 4: A 3-year-old is brought to the pediatrician by his mother because she is concerned about recent changes to his behavior. She states that he has seemed to regress in his motor development and has been having occasional brief episodes of uncontrollable shaking. During the subsequent work up, a muscle biopsy is obtained which demonstrates red ragged fibers and a presumptive diagnosis of a genetic disease made. The mother asks if her other son will be affected. What should be the physician's response?

• A. There is a 50% chance he will be affected
• B. There is a 100% chance he will be affected, and the severity will be the same
• C. There is a 25% chance he will be affected
• D. There is a 100% chance he will be affected, but the severity may be different (Correct Answer)
• E. He will be unaffected

Genetic disorders Explanation: ***There is a 100% chance he will be affected, but the severity may be different*** - The patient's symptoms (motor regression, seizures, red ragged fibers on muscle biopsy) are classic for a **mitochondrial disorder**, which are inherited via **maternal inheritance**. - All children of an affected mother will inherit the affected mitochondria; however, the **heteroplasmy** (proportion of mutated mitochondria inherited) can vary, leading to different disease severities. *There is a 50% chance he will be affected* - This inheritance pattern is typical for **autosomal dominant** disorders, or occasionally X-linked disorders in males. - Mitochondrial disorders do not follow autosomal dominant inheritance, as they are exclusively inherited from the mother. *There is a 100% chance he will be affected, and the severity will be the same* - While there is a 100% chance of inheriting the mutated mitochondria from an affected mother, the **phenotypic expression and severity can vary widely** due to heteroplasmy. - The proportion of mutated mitochondria can differ in various tissues and between offspring, leading to variable clinical manifestations. *There is a 25% chance he will be affected* - This represents the risk of inheritance for an **autosomal recessive** disorder when both parents are carriers. - Mitochondrial inheritance does not follow an autosomal recessive pattern. *He will be unaffected* - This would only be true if the mother's mitochondrial DNA were not affected or if the inheritance pattern allowed for some children to be completely spared, which is not the case for mitochondrial disorders. - Since the mother is the carrier of the mitochondrial mutation, all her children will inherit the mutated mitochondria.

Genetic disorders US Medical PG Question 5: A 9-year-old boy is brought to the physician because his parents are concerned that he has been unable to keep up with his classmates at school. He is at the 4th percentile for height and at the 15th percentile for weight. Physical examination shows dysmorphic facial features. Psychologic testing shows impaired intellectual and adaptive functions. Genetic analysis shows a deletion of the long arm of chromosome 7. Which of the following is the most likely additional finding in this patient?

• A. Absent thymus gland
• B. Supravalvular aortic stenosis (Correct Answer)
• C. Brushfield spots on the iris
• D. Testicular enlargement
• E. Hand flapping movements

Genetic disorders Explanation: ***Supravalvular aortic stenosis*** - The clinical presentation, including **dysmorphic facial features**, **growth restriction**, and **intellectual disability**, coupled with a **deletion on the long arm of chromosome 7**, is highly suggestive of **Williams syndrome**. - **Supravalvular aortic stenosis** is a classic cardiovascular finding in **Williams syndrome**, present in about 75% of affected individuals. *Absent thymus gland* - An absent thymus gland is characteristic of **DiGeorge syndrome**, which is caused by a **deletion on chromosome 22q11**. - This patient's genetic analysis indicates a deletion on **chromosome 7**, not chromosome 22. *Brushfield spots on the iris* - **Brushfield spots** are characteristic of **Down syndrome** (**trisomy 21**). - The genetic finding of a **deletion on chromosome 7** rules out Down syndrome as the underlying cause. *Testicular enlargement* - **Testicular enlargement** is a hallmark feature of **Fragile X syndrome**, a genetic condition caused by an **FMR1 gene mutation** on the X chromosome. - This patient's symptoms and genetic findings of a **chromosome 7 deletion** are not consistent with Fragile X syndrome. *Hand flapping movements* - **Hand flapping** is a common repetitive behavior observed in individuals with **autism spectrum disorder** and is also seen in some other genetic conditions like **Rett syndrome**. - While individuals with Williams syndrome may have unique behavioral profiles, hand flapping is not a specific or typical feature of the syndrome, and the genetic finding points to Williams syndrome.

Genetic disorders US Medical PG Question 6: A 4-year-old boy is brought to a pediatrician by his parents for a consultation after his teacher complained about his inability to focus or make friends at school. They mention that the boy does not interact well with others at home, school, or daycare. On physical examination, his vital signs are stable with normal weight, height, and head circumference for his age and sex. His general examination and neurologic examination are completely normal. A recent audiological evaluation shows normal hearing, and intellectual disability has been ruled out by a clinical psychologist. Which of the following investigations is indicated as part of his diagnostic evaluation at present?

• A. Magnetic resonance imaging (MRI) of brain
• B. Electroencephalography
• C. No further testing is needed
• D. Positron Emission Tomography (PET) scanning of head
• E. Autism spectrum disorder screening and developmental assessment (Correct Answer)

Genetic disorders Explanation: ***Autism spectrum disorder screening and developmental assessment*** - The clinical presentation (inability to focus, difficulty making friends, poor social interaction across multiple settings) is **highly suggestive of Autism Spectrum Disorder (ASD)**. - After ruling out **hearing impairment and intellectual disability**, the next appropriate step is **formal ASD screening using validated tools** such as the **Modified Checklist for Autism in Toddlers (M-CHAT)**, **Autism Diagnostic Observation Schedule (ADOS)**, or **Autism Diagnostic Interview-Revised (ADI-R)**. - According to **AAP guidelines**, when developmental concerns suggestive of ASD are identified, formal screening and comprehensive developmental assessment are **essential components of the diagnostic evaluation**. - ASD diagnosis is primarily **clinical**, based on standardized screening tools and developmental assessments, not neuroimaging or electrophysiological studies. *No further testing is needed* - This is **incorrect** because the patient has not yet undergone **formal ASD-specific screening and developmental assessment**. - While hearing and intellectual disability have been ruled out, **diagnostic confirmation of ASD** requires structured evaluation using validated assessment tools. - Simply observing symptoms without formal screening is inadequate for establishing an ASD diagnosis. *Magnetic resonance imaging (MRI) of brain* - Brain MRI is **not routinely indicated** for ASD diagnosis as it typically shows **normal findings** in children with ASD. - Neuroimaging is reserved for cases with **focal neurological signs, regression, or atypical features** suggesting structural abnormalities. - This patient has a **normal neurological examination**, making MRI unnecessary. *Electroencephalography* - EEG is indicated only when there is suspicion of **seizure disorder** or other specific neurological conditions. - The patient has a **normal neurological examination** with no seizure-like symptoms, making EEG unnecessary at this stage. *Positron Emission Tomography (PET) scanning of head* - PET scans are **not part of routine ASD diagnostic workup** and are typically used in research settings or for evaluating specific metabolic or neoplastic conditions. - The **radiation exposure and invasiveness** make PET scanning inappropriate for initial diagnostic evaluation in a child with developmental concerns.

Genetic disorders US Medical PG Question 7: A 4-year-old boy is brought to the pediatrician by his mother who is concerned about progressive leg weakness. His mother reports that the patient used to play outside with their neighbors for hours, but for the past few months she has seen him sitting on the sidewalk after 15 minutes because he’s too tired. The patient says his legs are “sleepy.” The patient’s mother has also had to remove the carpets from the house because the patient kept tripping over the edges. The mother reports that the patient is shy but cooperates well with his siblings and other children. He can say his first and last name and just started counting. His mother states he learned to fully walk by 15 months of age. He was hospitalized for bronchiolitis at 12 months of age, which resolved with supportive care. He had an uncomplicated orchiopexy surgery for undescended testes at 7 months of age. He has no other chronic medical conditions and takes no medications. He is up to date on his vaccinations including a flu vaccine 2 weeks ago. The patient’s mother has systemic lupus erythematous and his paternal uncle has dermatomyositis. On physical examination, bilateral calves are large in circumference compared to the thighs. Strength is 3/5 in bilateral quadriceps and 4/5 in bilateral calves. Sensation is intact. Achilles tendon reflexes are 1+ bilaterally. The patient can hop on one leg, but gets tired after 10 jumps. He has a slight waddling gait. Which of the following is the most appropriate test to confirm the diagnosis?

• A. Genetic testing (Correct Answer)
• B. Creatine kinase level
• C. Muscle biopsy
• D. Nerve conduction study
• E. Acetylcholine receptor antibody level

Genetic disorders Explanation: ***Genetic testing*** - **Genetic testing** for mutations in the **dystrophin gene** is the **definitive confirmatory test** for Duchenne Muscular Dystrophy (DMD). - The clinical presentation of **progressive proximal weakness**, **calf pseudohypertrophy**, **waddling gait**, **delayed motor milestones** (walking at 15 months), and **easy fatigability** in a young boy is classic for DMD. - **Deletion or duplication analysis** of the dystrophin gene identifies mutations in approximately **98% of DMD cases**, making it the most appropriate test to **confirm the diagnosis**. - Current DMD care guidelines (2018) recommend genetic testing as the primary confirmatory diagnostic test. *Creatine kinase level* - **Elevated CK** (typically 10-100 times normal) is a hallmark finding in DMD and is often the **initial screening test**. - While highly sensitive, **CK elevation is not specific** to DMD—it can be elevated in other muscular dystrophies, inflammatory myopathies, and even after vigorous exercise. - CK levels confirm muscle damage but do not establish the specific diagnosis of DMD, making it an excellent screening tool but not a confirmatory test. *Muscle biopsy* - **Muscle biopsy** can demonstrate **dystrophic changes** (fiber size variation, necrosis, regeneration, endomysial fibrosis) and **absence or reduction of dystrophin protein** on immunohistochemistry. - This was historically the gold standard but is **more invasive** than genetic testing and is now typically reserved for cases where **genetic testing is inconclusive** or atypical presentations. *Nerve conduction study* - **Nerve conduction studies** evaluate peripheral nerve function and are used to diagnose **neuropathies** (e.g., Charcot-Marie-Tooth disease). - This patient has a **myopathy** (primary muscle disease), not a neuropathy, so NCS would be **normal** and not helpful for diagnosis. *Acetylcholine receptor antibody level* - **Acetylcholine receptor antibodies** are positive in **myasthenia gravis**, a neuromuscular junction disorder. - Myasthenia gravis presents with **fluctuating weakness** (worse with activity, improves with rest), often with **ptosis and diplopia**, which does not match this presentation of progressive proximal muscle weakness.

Genetic disorders US Medical PG Question 8: A 12-hour old male infant is seen in the newborn nursery. He was born full term by vaginal delivery to a 40-year-old G4P3-->4 mother. Her pregnancy and delivery were uncomplicated, notable only for declining genetic testing. On exam, her son has a flat face, a fold in the upper eyelid, palpebral fissures that appear to slant upwards, and small ears. The diagnostic test for her son’s most likely condition should be conducted during which of the following phases of the cell cycle?

• A. S-phase
• B. Anaphase
• C. Prophase
• D. Metaphase (Correct Answer)
• E. Telophase

Genetic disorders Explanation: ***Metaphase*** - The infant's features (flat face, upslanting palpebral fissures, epicanthal folds) are **characteristic of Down syndrome** (Trisomy 21). - Karyotyping, which visualizes chromosomes to detect trisomies, is best performed during **metaphase** because chromosomes are maximally condensed and aligned at the metaphase plate, making them easily distinguishable. *S-phase* - During the **S-phase**, DNA replication occurs, and chromosomes are not yet condensed, making them unsuitable for microscopic visualization and karyotyping. - This phase is primarily for **DNA synthesis**, not chromosomal analysis. *Anaphase* - In **anaphase**, sister chromatids separate and move to opposite poles of the cell. - While chromosomes are visible, they are in motion, making it challenging to **accurately count and analyze their structure**. *Prophase* - **Prophase** involves the condensation of chromosomes and the breakdown of the nuclear envelope. - Chromosomes are still condensing in prophase and not yet fully aligned, making them less ideal for detailed **karyotype analysis compared to metaphase**. *Telophase* - In **telophase**, chromosomes decondense, the nuclear envelope reforms, and the cell divides into two. - Chromosomes are no longer discrete or condensed enough for **accurate visualization and karyotyping** during this phase.

Genetic disorders US Medical PG Question 9: A 2300-g (5.07-lb) male newborn is delivered at term to a 39-year-old woman. Examination shows a sloping forehead, a flat nasal bridge, increased interocular distance, low-set ears, a protruding tongue, a single palmar crease and an increased gap between the first and second toe. There are small white and brown spots in the periphery of both irises. The abdomen is distended. An x-ray of the abdomen shows two large air-filled spaces in the upper quadrant. This patient's condition is most likely associated with which of the following cardiac anomalies?

• A. Atrioventricular septal defect (Correct Answer)
• B. Tetralogy of Fallot
• C. Atrial septal defect
• D. Patent ductus arteriosus
• E. Ventricular septal defect

Genetic disorders Explanation: ***Atrioventricular septal defect*** - The constellation of dysmorphic features (sloping forehead, flat nasal bridge, low-set ears, protruding tongue, single palmar crease, increased gap between first and second toe, Brushfield spots) and **duodenal atresia** (double bubble sign on X-ray) are highly suggestive of **Down syndrome** (Trisomy 21). - **Atrioventricular septal defects (AVSDs)**, also known as endocardial cushion defects, are the most common and classic cardiac anomaly associated with **Down syndrome**, occurring in about 40-50% of affected children. *Tetralogy of Fallot* - While **Tetralogy of Fallot** is a cyanotic heart defect, it is not the most common cardiac anomaly associated with Down syndrome. - It involves four specific defects: **ventricular septal defect**, **pulmonary stenosis**, **overriding aorta**, and **right ventricular hypertrophy**. *Atrial septal defects* - **Atrial septal defects (ASDs)** are a type of congenital heart defect where there is a hole in the septum between the two atria of the heart. - While ASDs can occur in Down syndrome, they are less common than AVSDs and are often part of a more complex AVSD rather than isolated. *Patent ductus arteriosus* - **Patent ductus arteriosus (PDA)** is the persistence of the fetal ductus arteriosus in a newborn after birth. - While PDAs can occur in infants with Down syndrome, they are also very common in **premature infants** and are not the most characteristic cardiac lesion. *Ventricular septal defect* - **Ventricular septal defect (VSD)** is a hole in the septum separating the two ventricles of the heart. - VSDs are common congenital heart defects and can be found in Down syndrome, but **AVSDs** are more specific and prevalent in this condition, often involving a component of a VSD.

Genetic disorders US Medical PG Question 10: The medical student on the pediatric cardiology team is examining a 9-year-old girl who was referred by her primary care physician for unexplained hypertension. She is accompanied by her mother who reveals that the child is generally well but has been significantly less active than her peers for the past year. On exam, the medical student notes a thin girl in no apparent distress appearing slightly younger than stated age. Vital signs reveal a BP is 160/80, HR 80, RR 16. Physical exam is notable only for a clicking sound is noted around the time of systole but otherwise the cardiac exam is normal. Pedal pulses could not be palpated. Which of the following physical exam findings was most likely missed by both the medical student and primary care physician?

• A. Long philtrum
• B. Prominent occiput
• C. Webbed neck (Correct Answer)
• D. Cleft palate
• E. Single palmar crease

Genetic disorders Explanation: ***Webbed neck*** - The combination of **hypertension** with **unpalpable pedal pulses** and a **systolic click** in a pediatric patient strongly suggests **coarctation of the aorta**. - **Webbed neck** (or **pterygium colli**) is a classic phenotypic feature associated with **Turner syndrome**, which frequently co-occurs with coarctation of the aorta. *Long philtrum* - A **long philtrum** is a craniofacial feature sometimes associated with certain genetic syndromes like **fetal alcohol syndrome** or **Marfan syndrome**, but it is not specifically linked to coarctation of the aorta or Turner syndrome. - While these syndromes can have cardiovascular manifestations, a long philtrum does not directly point to the specific findings presented. *Prominent occiput* - A **prominent occiput** is a non-specific finding that can be seen in various conditions, including some **chromosomal abnormalities** or **skeletal dysplasias**. - It is not a characteristic feature of **Turner syndrome** or **coarctation of the aorta**. *Cleft palate* - **Cleft palate** is a birth defect affecting the roof of the mouth, often associated with a wide range of genetic or environmental factors. - While patients with cleft palate can have associated congenital heart defects, it is not a direct or common association with **Turner syndrome** or **coarctation of the aorta**. *Single palmar crease* - A **single palmar crease** (simian crease) is a dermatoglyphic feature often associated with **Down syndrome** (Trisomy 21). - While Down syndrome is associated with various congenital heart defects (e.g., AV septal defect), it is not typically associated with **coarctation of the aorta** or **Turner syndrome**.

Genetic disorders Flashcard 1 of 10

Question: What pathology is characterized by insatiable appetite (hyperphagia), obesity, intellectual disability, and hypogonadism? _____

Answer: Prader-Willi syndrome

Genetic disorders Flashcard 2 of 10

Question: What pathology is characterized by inappropriate laughter, seizures, ataxia, and severe intellectual disability?_____

Answer: Angelman syndrome

Genetic disorders Flashcard 3 of 10

Question: What pathology is associated with an enlarged jaw, testes, and ears?_____

Answer: Fragile X syndrome

Genetic disorders Flashcard 4 of 10

Question: _____ syndrome is a form of long QT syndrome that involves sensorineural deafness

Answer: Jervell and Lange-Nielsen

Genetic disorders Flashcard 5 of 10

Question: Hunter's syndrome

Answer:

Extra Information: accumulation of heparan/dermatan sulfatemild: developmental delay, gargoylism, airway obstruction, hepatosplenomegaly + aggressive behavior - corneal clouding XRiduronate sulfatase

Genetic disorders Flashcard 6 of 10

Question: Hurler's syndrome

Answer:

Extra Information: accumulation of heparan/dermatan sulfatedevelopmental delay, gargoylism, airway obstruction, corneal clouding, hepatosplenomegalyARα-L-iduronidase

Genetic disorders Flashcard 7 of 10

Question: What manifestation of 22q11 deletion syndrome define velocardiofacial syndrome?

Answer: cardiac, palate, facial defects

Genetic disorders Flashcard 8 of 10

Question: Williams syndrome

Answer:

Extra Information: elfin facies, mild retardation, hyper-verbal, hyper-friendly, diverse cardiovascular problemshypercalcemia7q microdeletion (including elastin gene)

Genetic disorders Flashcard 9 of 10

Question: Prader-Willi syndrome

Answer:

Extra Information: mental retardation, hyperphagia, obesity, hypogonadism, hypotoniaimprinting disease; defect in the paternal genespaternal chromosome 15

Genetic disorders Flashcard 10 of 10

Question: X-linked recessive

Answer: yes, but only through females

Extra Information: many more males affectedno male-to-male transmission