CHRNG and spondylometaphyseal dysplasia: Of the six couples with prior progeny showing syndromic findings, five had known pathogenic variants confirming a genetic disorder, including arginosuccinic aciduria (ASL gene), Escobar syndrome (CHRNG gene), spondylometaphyseal dysplasia (DDR2 gene), de Barsy progeria (PYCR1 gene), and infantile hypotonia with psychomotor retardation and characteristic facies-3 (TBCK gene) (Table).