Congenital defects — MCQs

An 8-year-old child with “elfin” facial features is very friendly with strangers. He has a history of mild mental retardation, and a hemizygous deletion on chromosome 7q11.23, that includes a portion of the elastin gene. Which of the following is most likely true in this patient?

A 15-year-old boy is brought to the physician by his mother for a well-child examination. He recently stopped attending his swim classes. The patient is at the 97th percentile for height and the 50th percentile for weight. Examination shows decreased facial hair, bilateral breast enlargement, and long extremities. Genital examination shows scant pubic hair, small testes, and a normal-sized penis. Further evaluation is most likely to show which of the following karyotypes?

A 5-year-old girl is brought to the emergency department by her mother with seizures. The blood glucose is 94 mg/dl and the serum calcium is 5.3 mg/dl; however, the PTH levels are low. The medical history includes a delay in achieving developmental milestones. Her mother also says she needs frequent hospital visits due to recurrent bouts with the flu. The cardiovascular examination is within normal limits. What is the most likely cause underlying this presentation?

A 14-year-old boy is brought to the physician because of increasing swelling of his legs and generalized fatigue for 1 month. During this period he has also had a productive cough and shortness of breath. He has been unable to carry out his daily activities. He has a history of recurrent respiratory tract infections and chronic nasal congestion since childhood. He has a 3-month history of foul-smelling and greasy stools. He is at 4th percentile for height and weight. His temperature is 37°C (98.6°F), pulse is 112/min, respirations are 23/min, and blood pressure is 104/64 mm Hg. Examination shows clubbing of his fingers and scoliosis. There is 2+ pitting edema of the lower extremities. Jugular venous distention is present. Inspiratory crackles are heard in the thorax. Cardiac examination shows a loud S2. The abdomen is mildly distended and the liver is palpated 2 cm below the right costal margin. Hepato-jugular reflux is present. Which of the following is the most likely diagnosis?

A 6-year-old male presents to the pediatrician with seizures. His mother reports that the patient has had two seizures lasting about 30 seconds each over the last three days. She reports that the patient has previously had seizures a few times per year since he was 12 months of age. The patient’s past medical history is otherwise notable for intellectual disability. He rolled over at 14 months of age and walked at 24 months of age. The patient’s mother denies any family history of epilepsy or other neurologic diseases. The patient is in the 3rd percentile for height and the 15th percentile for weight. On physical exam, he has a happy demeanor with frequent smiling. The patient has strabismus and an ataxic gait accompanied by flapping of the hands. He responds intermittently to questions with one-word answers. This patient is most likely to have which of the following genetic abnormalities?

A 4-month-old male infant is brought to the physician by his father because of swelling of his left hemiscrotum. He has otherwise been healthy and is gaining weight appropriately. Physical examination shows a nontender left scrotal mass that transilluminates. The mass increases in size when the boy cries but is easily reducible. Which of the following is the most likely underlying cause of this patient's findings?

An inconsolable mother brings her 2-year-old son to the emergency room after finding a large amount of bright red blood in his diaper, an hour ago. She states that for the past week her son has been having crying fits while curling his legs towards his chest in a fetal position. His crying resolves either after vomiting or passing fecal material. Currently, the child is in no apparent distress. Physical examination with palpation in the gastric region demonstrates no acute findings. X-ray of the abdominal area demonstrates no acute findings. His current temperature is 36.5°C (97.8°F), heart rate is 93/min, blood pressure is 100/64 mm Hg, and respiratory rate is 26/min. His weight is 10.8 kg (24.0 lb), and height is 88.9 cm (35.0 in). Laboratory tests show the following: RBC count 5 million/mm3 Hematocrit 36% Hemoglobin 12 g/dL WBC count 6,000/mm3 Mean corpuscular volume 78 fL What is the most likely underlying embryological cause predisposing to this condition?

A 3-year-old male presents with his parents to a pediatrician for a new patient visit. The child was recently adopted and little is known about his prior medical or family history. The parents report that the child seems to be doing well, but they are concerned because the patient is much larger than any of the other 3-year-olds in his preschool class. They report that he eats a varied diet at home, and that they limit juice and snack foods. On physical exam, the patient is in the 73rd percentile for weight, 99th percentile for height, and 86th percentile for head circumference. He appears mildly developmentally delayed. He has a fair complexion and tall stature with a prominent sternum. The patient also has joint hypermobility and hyperelastic skin. He appears to have poor visual acuity and is referred to an ophthalmologist, who diagnoses upward lens subluxation of the right eye. This child is most likely to develop which of the following complications?

A 15-month-old boy is brought to the pediatrician for immunizations and assessment. His parents report that he is eating well and produces several wet diapers every day. He is occasionally fussy, but overall a happy and curious child. The boy was born at 39 weeks gestation via spontaneous vaginal delivery. On physical examination his vital signs are stable. His weight and height are above the 85th percentile for his age and sex. On chest auscultation, the pediatrician detects a loud harsh holosystolic murmur over the left lower sternal border. The first and second heart sounds are normal. An echocardiogram confirms the diagnosis of the muscular ventricular septal defect without pulmonary hypertension. Which of the following is the best management strategy for this patient?

A 7-year-old boy is brought to his pediatrician by his mother who is worried about his clumsiness. She states that over the past 3 months she has noticed progressive weakness. He used to climb trees and run outside with his cousins, but now he says he gets “too tired.” She’s recently noticed him starting to “walk funny,” despite having “muscular legs.” Upon physical examination, the patient has calf muscle hypertrophy. He uses his arms to rise out of the chair. Labs are obtained that show an elevated creatine kinase. Genetic analysis detects a dystropin gene mutation. A muscle biopsy is performed that reveals reduced dystrophin. Which of the following is the most likely diagnosis?