P507: Tetrasomy 9p in a patient affected with dilated cardiomyopathy: Incidental finding or extended phenotype?

Outcome and Follow-Up: Physical Medicine and Rehabilitation evaluated the patient at 10 months old and reported overall improvement in his developmental milestones.He continued to gain weight appropriately and his anemia improved.He is scheduled to follow-up in genetics clinic for reassessment in 2 years and will be followed by neurology for seizure monitoring.With his early interventions in place, he will continue to receive the necessary support throughout childhood and as he enters school.Discussion: While all the patient's symptoms coincide with GAND, other neurodevelopmental disorders have similar presentations.Some of his symptoms, such as benign subarachnoid space enlargement, reflux, and laryngomalacia can be written off as "common pediatric findings" or that it will improve over time.It is uncertain the extent of his delays and how they compare to other GAND patients as he was diagnosed quite early.His language development and ambulation, while delayed, cannot accurately be compared to the other, older patients.Moreover, his variant has not yet been reported in the literature and whether his course will continue along the same pattern is unknown.Conclusion: It is well known that gene expression can be modified by the environment and the brain shows greater plasticity in early development.Therefore, early diagnosis and intervention can provide a pathway for these children to reach their greatest potential.The awareness and persistence of his mother allowed the patient to be seen by the necessary specialists and receive appropriate interventions in a timely manner.Introduction: GATAD2B associated neurodevelopmental disorder (GAND) is a rare condition present in about 400 individuals.Despite some symptoms presenting quite early, the average age of diagnosis is 6.8 years of age.Case Presentation: An 8-month-old boy presented to genetics clinic with concerns for mild, global developmental delay, macrocephaly, hypotonia and laryngomalacia.He was born full-term and had an uncomplicated delivery without NICU stay.At birth, the head circumference was 99th percentile and at 4 months, it remained in this range.He had trouble feeding with reflux, noisy feeding and chronic nasal congestion.His mother noticed he appeared more fatigued often.His eyes would cross at times.He did not appear to be holding his head up well or rolling over and he was vocalizing, but without consonants.His 2.5-year-old brother did not experience any delays in his development and there was no family history of intellectual disability, developmental delays or autism.Diagnostic Workup: MRI imaging demonstrated benign enlargement of subarachnoid spaces.He was diagnosed with laryngomalacia on flexible laryngoscopy and video fluoroscopic swallow study (VFSS) was consistent with oropharyngeal dysphagia.Esophagogastroduodenoscopy pathology noted reflux esophagitis.Additionally, ophthalmology reported sectional iris pigmentation, over-riding of the orbicularis muscle, and high hyperopic astigmatism, and his audiology assessment revealed middle ear dysfunction.Microarray ordered at 8 months of age identified a duplication on the long arm of chromosome 6 of uncertain significance involving genes AGPAT4 and PRKN.Fragile X screening was normal.Exome sequencing was significant for a novel, de novo heterozygous deletion G275Vfs*18 in GATAD2B consistent with a diagnosis of GAND.