Practical guidelines for managing patients with 22q11.2 deletion syndrome

A 12-year-old boy currently is followed by multiple sub-specialists for problems caused by the chromosome 22q11.2 deletion syndrome (22q11DS) (Figure). He was born via spontaneous vaginal delivery, weighing 3033 g, to a 31-year-old G3P3 mother after a full-term pregnancy complicated only by mild polyhydramnios. Family history was non-contributory. Apgar scores were 8 at 1 minute and 9 at 5 minutes. With the exception of a weak cry, the results of the infant’s initial examination were unremarkable, and he was moved to the well-baby nursery. Shortly thereafter, a cardiac murmur was noted, the cardiology department was consulted, and the child was transferred to a local tertiary care facility with a diagnosis of tetralogy of Fallot. Stable, he was discharged home at 3 days of life. Figure Mild dysmorphic facial features of a boy aged 11 years with 22q11.2DS, including a short forehead, hooded eyelids with upslanting palpebral fissures, malar flatness, bulbous nasal tip with hypoplastic alae nasi, and protuberant ears. At 5 days of life, he had jerky movements. On presentation to the local emergency department, his total calcium level was 4.7 mg/dL, and later partial hypoparathyroidism was diagnosed. At that time, a consulting geneticist suggested the diagnosis of chromosome 22q11DS. Weeks later, the family received a telephone call confirming the diagnosis with fluorescence in situ hybridization (FISH). No additional information about the diagnosis, prognosis, etiology, or recurrence risk was provided until the child was 5 months of age, when he underwent cardiac repair at a third hospital, where a comprehensive 22q11DS program was in operation. In the interim, the child had feeding difficulties requiring supplemental nasogastric tube feeds, nasal regurgitation, and gastroesophageal reflux, while the parents searched the internet for reliable information about their son’s diagnosis. Subsequent notable abnormalities and interventions included: recurrent otitis media with bilateral myringotomy tube placement at 6 months; angioplasty with left pulmonary artery stent placement after the identification of pulmonary artery stenosis with bilateral pleural effusions at age 6 years; chronic upper respiratory infections with significant T cell dysfunction requiring live viral vaccines to be held until age 7 years; velopharyngeal incompetence necessitating posterior pharyngeal flap surgery at 7 years; enamel hypoplasia and numerous caries resulting in 3 separate dental procedures under general cardiac anesthesia beginning at age 7 years; multiple cervical and thoracic vertebral anomalies with thoracic levoconvex scoliosis and upper lumbar dextroscoliosis requiring growing rod placement at age 11 years with subsequent rod extension at ages 11.5 and 12 years; postoperative hypocalcemia; short stature; constipation; and persistent idiopathic thrombocytopenia. Pertinent negative test results included normal renal ultrasound scanning and parental 22q11.2 deletion studies. On physical examination, the boy’s height and weight have consistently tracked just below the fifth percentile, with no evidence of growth hormone deficiency. His head circumference is within reference range at the 25th percentile. Dysmorphic features include: a low anterior hairline; hooded eyelids; malar flatness; normally formed but protuberant ears with attached lobes; a mildly deviated nose with a bulbous nasal tip and hypoplastic alae nasi; asymmetric crying facies with a thin upper lip; mild micrognathia; a sacral dimple; and soft tissue syndactyly of the second and third toes. Developmentally, the boy had mild delays in achieving motor milestones, sitting at 11 months and walking at 18 months. However, he exhibited significant delays in the emergence of language: he never babbled, spoke his first words at age 3 years, and only achieved full conversational speech at 7 years. However, he had relative strengths in receptive language and communicated appropriately by the use of sign language. Now quite conversant, he is mainstreamed in the seventh grade with resource room supports. Moreover, he is affable, but exhibits anxiety and perseverations. Lastly, despite numerous medical, academic, and social challenges, he participates in assisted athletics, is an avid wrestling fan, and enjoys travel. However, his exceptionally supportive parents, siblings, and extended family continue to worry about his long-term outcome and transition of care as he approaches adulthood. As demonstrated by this boy’s complicated course, practical multi-system guidelines are needed to assist the general practitioner and specialists in caring for patients with 22q11DS. Although still under-recognized, detection, including in the prenatal setting, is increasing. Moreover, the phenotypic spectrum is highly variable, and patients may present at any age. Thus, initial guidelines developed by an international panel of experts present the best practice recommendations currently available across the lifespan, with a major focus on the changing issues through childhood development.