Bernard B is 4-years-old and has been followed by his pediatrician for a diagnosis of motor and speech delay. His parents became concerned when Bernard still couldn’t walk at age 13 months. He sat up at 8 months, crawled at 9 months, and walked at 18 months. Bernard began to speak at age 2 years and now has a vocabulary of about 30 words; he understands many more but cannot use phrases. He often repeats the same syllable. He also has had sensory differences and is extremely sensitive to loud or background noises (eg, vacuum cleaners, lawn mowers), food textures (he avoids smooth foods like yogurt), and certain clothes (he cannot tolerate labels in clothing, dislikes wearing shoes and socks). His parents were asked to remove him from his preschool because he will not relate to other children, and often hits or bites them.
Bernard’s full term uncomplicated pregnancy ended in spontaneous vaginal delivery. He had good Apgar scores, weighed 8 lbs at birth, and had normal neonatal screening. A family history revealed that his mother’s brother had mental disability with autistic behaviors, and that a 6-year-old son of one of his mother’s sisters had significant developmental delays. Bernard’s mother is 37 and his father is 38; neither has health problems. The parents are anxious to know if their son has a disability that could be hereditary since they wish to have another child and are concerned about their older age.
On physical examination, Bernard had a relatively normal facial appearance with large, flexible ears and a prominent jaw. He had a mild pectus excavatum with increased joint laxity. He was very active during the examination and repeatedly turned the lights on and off and tried to open the door. He did not observe social boundaries; he grabbed at pens or exam instruments, sought hugs from his parents, and ignored their commands.
1. What characteristics of the family history and facial appearance suggest a genetic diagnosis for Bernard?
2. What behavioral diagnoses would you consider for Bernard?
3. What laboratory tests would you order to confirm your diagnosis?
4. What would be the parents’ risks for similar genetic abnormalities in future children?
Answers can be found on the next page.