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4. Pediatrics MCQs

Practice Set 188 of 334

This practice set contains high-yield board review questions covering key concepts in 4. Pediatrics. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 3741

Topic: 4. Pediatrics

Chondroectodermal dysplasia (Ellis-van Creveld syndrome) shares phenotypic similarities with achondroplasia due to the proximity of its genetic marker to the FGFR3 gene. However, it can be distinguished clinically by the presence of specific features. Which of the following features is characteristic of Ellis-van Creveld syndrome but NOT typical of achondroplasia?

. Disproportionate dwarfism
. Short limbs
. Postaxial polydactyly
. Frontal bossing
. Rhizomelic shortening

Correct Answer & Explanation

. Postaxial polydactyly

Explanation

Correct Answer: CWhile both conditions present with short stature and disproportionate dwarfism, postaxial polydactyly is a hallmark of Ellis-van Creveld syndrome and is not a typical feature of achondroplasia.

Question 3742

Topic: 4. Pediatrics

Ellis-van Creveld syndrome is a generalized disorder of the maturation of enchondral ossification. Genetic studies have linked the syndrome to the marker HOX7. This region is located proximal to the gene responsible for which of the following skeletal dysplasias?

. Osteogenesis imperfecta (COL1A1)
. Achondroplasia (FGFR3)
. Multiple epiphyseal dysplasia (COMP)
. Diastrophic dysplasia (SLC26A2)
. Cleidocranial dysplasia (RUNX2)

Correct Answer & Explanation

. Achondroplasia (FGFR3)

Explanation

Correct Answer: Achondroplasia (FGFR3)The gene for Ellis-van Creveld syndrome is linked to the marker HOX7, which is located in a region proximal to the FGFR3 gene. Mutations in the FGFR3 gene are responsible for achondroplasia. This genetic proximity is thought to be responsible for the achondroplasia-like phenotype (disproportionate dwarfism) seen in Ellis-van Creveld syndrome.

Question 3743

Topic: 4. Pediatrics

A pediatric patient with suspected Ellis-van Creveld syndrome is being examined. Alongside short stature and polydactyly, the examiner evaluates the patient's oral cavity. Which of the following oral findings is highly characteristic of this syndrome?

. Cleft palate without cleft lip
. Mandibular prognathism
. Fusion of the upper lip to the gingival margin
. Bifid uvula
. Macroglossia

Correct Answer & Explanation

. Fusion of the upper lip to the gingival margin

Explanation

Correct Answer: Fusion of the upper lip to the gingival marginVariable oral findings play an important role in the diagnosis of Ellis-van Creveld syndrome. These include fusion of the upper lip to the gingival margin, multiple frenula, abnormally shaped and microdontic teeth, congenitally missing teeth, malocclusion, neonatal teeth, and notching of the lower alveolar process.

Question 3744

Topic: 4. Pediatrics

Parents of a child recently diagnosed with Ellis-van Creveld syndrome are seeking genetic counseling regarding the risk of their future children being affected. What is the inheritance pattern of this condition?

. Autosomal dominant
. Autosomal recessive
. X-linked dominant
. X-linked recessive
. Mitochondrial

Correct Answer & Explanation

. Autosomal recessive

Explanation

Correct Answer: Autosomal recessiveEllis-van Creveld syndrome (chondroectodermal dysplasia) is an autosomal recessive disorder. This means that both parents must be carriers of the mutated gene for a child to be affected, giving a 25% chance of recurrence in subsequent pregnancies.

Question 3745

Topic: 4. Pediatrics

A 7-year-old child presents with the clinical appearance shown below. The patient has a history of neonatal teeth and a narrow chest. Which of the following additional skeletal anomalies is frequently associated with this patient's condition?


. Absence of clavicles
. Atlantoaxial instability
. Congenital pseudoarthrosis of the tibia
. Proximal focal femoral deficiency
. Radial clubhand

Correct Answer & Explanation

. Absence of clavicles

Explanation

Correct Answer: Absence of claviclesThe image shows a patient with short stature, disproportionate dwarfism, and fusion of the upper lip to the gingival margin, characteristic of Ellis-van Creveld syndrome. Other skeletal and systemic associations include the absence of clavicles, a narrow chest, hypoplastic maxilla, and urinary tract anomalies.

Question 3746

Topic: 4. Pediatrics

Genetic mapping of Ellis-van Creveld syndrome has linked the responsible gene to the marker HOX7. This region is proximal to the FGFR3 gene. According to the provided literature, this genetic proximity is responsible for which aspect of the patient's clinical presentation?

. The achondroplasia phenotype (disproportionate dwarfism)
. The presence of postaxial polydactyly
. The development of ventricular septal defects
. The manifestation of ectodermal dysplasia
. The fusion of the upper lip to the gingival margin

Correct Answer & Explanation

. The achondroplasia phenotype (disproportionate dwarfism)

Explanation

Correct Answer: The achondroplasia phenotype (disproportionate dwarfism)The link of the Ellis-van Creveld syndrome gene to the marker HOX7 in a region proximal to the FGFR3 gene is responsible for the achondroplasia phenotype, which manifests clinically as disproportionate dwarfism and short limbs.

Question 3747

Topic: 4. Pediatrics

Chondroectodermal dysplasia (Ellis-van Creveld syndrome) is an autosomal recessive disorder characterized by short limbs and polydactyly. The genetic defect responsible for this syndrome is linked to which of the following markers, located proximal to the FGFR3 gene?

. SOX9
. HOX7
. RUNX2
. COL1A1
. COMP

Correct Answer & Explanation

. HOX7

Explanation

Correct Answer: HOX7The link of the Ellis-van Creveld's syndrome gene to marker HOX7 in a region proximal to the FGFR3 gene is responsible for the achondroplasia-like phenotype seen in this condition.

Question 3748

Topic: 4. Pediatrics

A 2-year-old child with Ellis-van Creveld syndrome is scheduled for surgical excision of postaxial polydactyly. Preoperative clearance is essential due to the high incidence of congenital heart disease in this population. Which of the following is the most common cardiac anomaly associated with this syndrome?

. Tetralogy of Fallot
. Transposition of the great arteries
. Ventricular septal defect
. Patent ductus arteriosus
. Coarctation of the aorta

Correct Answer & Explanation

. Ventricular septal defect

Explanation

Correct Answer: Ventricular septal defectEllis-van Creveld syndrome is classically characterized by congenital heart disease, most commonly due to a ventricular septal defect (VSD) or a common atrium.

Question 3749

Topic: 4. Pediatrics

Parents of a child recently diagnosed with chondroectodermal dysplasia are seeking genetic counseling regarding the risk of having another affected child. What is the inheritance pattern of this syndrome?

. Autosomal dominant
. Autosomal recessive
. X-linked dominant
. X-linked recessive
. Mitochondrial

Correct Answer & Explanation

. Autosomal recessive

Explanation

Correct Answer: Autosomal recessiveEllis-van Creveld syndrome is an autosomal recessive disorder. Therefore, if both parents are carriers, there is a 25% chance with each pregnancy of having an affected child.

Question 3750

Topic: 4. Pediatrics

Which of the following genetic markers is closely linked to the gene responsible for the syndrome characterized by the clinical findings shown below?




. COL1A1
. HOX7
. COMP
. SOX9

Correct Answer & Explanation

. HOX7

Explanation

Correct Answer: HOX7The clinical image demonstrates short stature and disproportionate dwarfism characteristic of Ellis-van Creveld's syndrome (Chondroectodermal Dysplasia). The text specifies that the link of the Ellis-van Creveld's syndrome gene is to the marker HOX7, located in a region proximal to the FGFR3 gene.

Question 3751

Topic: 4. Pediatrics

Which of the following oral findings is a characteristic feature of the syndrome associated with the clinical presentation shown below?




. Cleft palate without lip involvement
. Fusion of the upper lip to the gingival margin
. Mandibular prognathism
. Blue sclera and dentinogenesis imperfecta

Correct Answer & Explanation

. Fusion of the upper lip to the gingival margin

Explanation

Correct Answer: Fusion of the upper lip to the gingival marginVariable oral findings play an important role in the diagnosis of Ellis-van Creveld's syndrome. These include fusion of the upper lip to the gingival margin, multiple frenula, abnormally shaped and microdontic teeth, congenitally missing teeth, malocclusion, neonatal teeth, and notching of the lower alveolar process.

Question 3752

Topic: 4. Pediatrics

What is the inheritance pattern of the syndrome characterized by the foot deformities shown below, along with short limbs and congenital heart disease?




. Autosomal dominant
. Autosomal recessive
. X-linked recessive
. Mitochondrial

Correct Answer & Explanation

. Autosomal recessive

Explanation

Correct Answer: Autosomal recessiveThe image demonstrates shortening of the digits of the toes and feet, consistent with Ellis-van Creveld's syndrome. This syndrome is inherited in an autosomal recessive pattern.

Question 3753

Topic: Pediatric Hip

In addition to the short and thick tubular bones seen in the radiograph below, what other skeletal anomaly is frequently associated with this syndrome?




. Absence of clavicles
. Scapular winging
. Atlantoaxial instability
. Coxa vara

Correct Answer & Explanation

. Absence of clavicles

Explanation

Correct Answer: Absence of claviclesEllis-van Creveld's syndrome is associated with several other skeletal and systemic anomalies, including the absence of clavicles, a narrow chest, and a hypoplastic maxilla.

Question 3754

Topic: 4. Pediatrics

The genetic mutation responsible for the syndrome depicted below is linked to the HOX7 marker. This region is located proximal to a gene that, when mutated, causes which of the following conditions?




. Osteogenesis imperfecta
. Achondroplasia
. Multiple hereditary exostoses
. Cleidocranial dysplasia

Correct Answer & Explanation

. Achondroplasia

Explanation

Correct Answer: AchondroplasiaThe text notes that the Ellis-van Creveld's syndrome gene is linked to the marker HOX7 in a region proximal to the FGFR3 gene. Mutations in the FGFR3 gene are responsible for the achondroplasia phenotype.

Question 3755

Topic: 4. Pediatrics

Which of the following describes the inheritance pattern and genetic mutation most commonly associated with Ellis-van Creveld syndrome?

. Autosomal dominant inheritance; FGFR3 mutation
. Autosomal recessive inheritance; EVC1 or EVC2 mutation
. X-linked recessive inheritance; COMP mutation
. Autosomal recessive inheritance; SLC26A2 mutation
. Autosomal dominant inheritance; COL1A1 mutation

Correct Answer & Explanation

. Autosomal recessive inheritance; EVC1 or EVC2 mutation

Explanation

Ellis-van Creveld (EVC) syndrome, or chondroectodermal dysplasia, is an autosomal recessive disorder caused by mutations in the EVC1 or EVC2 genes located on chromosome 4p16. These gene products are essential for normal Hedgehog signaling in the skeleton.

Question 3756

Topic: 4. Pediatrics

A neonate is diagnosed with Ellis-van Creveld syndrome. Which of the following patterns of limb shortening is most characteristic of this condition?

. Predominantly rhizomelic shortening
. Mesomelic and acromelic shortening
. Entirely proportionate short stature
. Asymmetric unilateral shortening
. Purely rhizomelic and diaphyseal shortening

Correct Answer & Explanation

. Mesomelic and acromelic shortening

Explanation

Unlike achondroplasia which is primarily rhizomelic, EVC syndrome presents with disproportionate short stature characterized by mesomelic (middle segment, e.g., forearms and lower legs) and acromelic (distal segment, e.g., hands and feet) shortening.

Question 3757

Topic: 4. Pediatrics

An infant with short stature, postaxial polydactyly, and hypoplastic nails is being evaluated. Which congenital cardiac anomaly is most classically associated with this patient's syndrome?

. Tetralogy of Fallot
. Ventricular septal defect
. Common atrium (single atrium)
. Patent ductus arteriosus
. Coarctation of the aorta

Correct Answer & Explanation

. Common atrium (single atrium)

Explanation

Approximately 50-60% of patients with EVC syndrome have a congenital heart defect. The most classic and frequent cardiac anomaly is an atrial septal defect, specifically a single or common atrium.

Question 3758

Topic: 4. Pediatrics

The genetic defect in Ellis-van Creveld syndrome disrupts the Hedgehog signaling pathway. Which zone of the physis is primarily affected by this disrupted endochondral ossification?

. Reserve zone
. Proliferative and hypertrophic zones
. Zone of provisional calcification
. Primary spongiosa
. Secondary spongiosa

Correct Answer & Explanation

. Proliferative and hypertrophic zones

Explanation

Indian Hedgehog (Ihh) signaling is crucial for regulating chondrocyte proliferation and differentiation. Mutations in EVC genes disrupt this pathway, primarily causing disorganized endochondral ossification in the proliferative and hypertrophic zones.

Question 3759

Topic: 4. Pediatrics

Which of the following best describes the inheritance pattern and genetic locus classically associated with Ellis-van Creveld syndrome?

. Autosomal recessive, 4p16
. Autosomal dominant, 4p16
. X-linked recessive, Xq28
. Autosomal dominant, FGFR3
. Autosomal recessive, COMP

Correct Answer & Explanation

. Autosomal recessive, 4p16

Explanation

Ellis-van Creveld syndrome is an autosomal recessive condition caused by mutations in the EVC or EVC2 genes. These genes are located on chromosome 4p16.

Question 3760

Topic: 4. Pediatrics

A neonate is diagnosed with chondroectodermal dysplasia. An echocardiogram is urgently ordered by the pediatric team. What is the most common cardiac anomaly expected in this condition?

. Ventricular septal defect
. Tetralogy of Fallot
. Common atrium / Atrial septal defect
. Transposition of the great arteries
. Coarctation of the aorta

Correct Answer & Explanation

. Common atrium / Atrial septal defect

Explanation

Congenital heart defects occur in approximately 50-60% of patients with Ellis-van Creveld syndrome. The most characteristic and common anomaly is a defect of atrial septation, primarily a common atrium or large atrial septal defect (ASD).

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