GestaltMatcher facial analysis helped confirm the diagnosis of Chung-Jansen Syndrome

We present a 13.5 year old boy with global developmental delay, mild intellectual disability (average IQ 67 points), obesity (BMI on 99th percentile, z +2.7), height on the 84th percentile for obesity and head circumference on the 96th percentile (z +1.8). The physical examination furthermore showed facial dysmorphism with long palpebral fissures, high nasal root, anteverted nares, long philtrum, large ears, tapering fingers, acanthosis nigricans, five small café-au-lait spots, one nevus spilus and gynecomastia. Duo Exome sequencing revealed a heterozygous not maternally inherited novel canonical splice site variant in the PHIP gene which in conjunction with the appropriate phenotype and high ranking of the suitable facial dysmorphism by GestaltMatcher could be classified as likely pathogenic. Family history is unremarkable for intellectual disability but the father is not available for testing. The younger maternal half brother has an expressive speech disorder, macrocephaly and obesity but without intellectual disability (average IQ 94 points). Genetic testing is planned to exclude a variable expressivity of Chung-Jansen Syndrome because of the possibility of a germline mosaicism in the mother.