The X-linked Opitz G/BBB Syndrome (XLOS) is associated with a number of clinical features. Its phenotype features overlap with the autosomal-dominant Opitz G/BBB syndrome (ADOS).

Chromosome: Xp22.2

Gene: MID1 (E3 ubiquitin-protein ligase midline 1)


Inheritance: X-linked


Clinical findings include:

(1) cleft lip and/or palate

(2) telecanthus and hypertelorism

(3) other facial features (prominent forehead, widow's peak, broad nasla bridge, anteverted nares)

(4) laryngotracheoesophageal defects

(5) developmental delay

(6) midline brain abnormalities including defects of corpus callosum and cerebellar vermis

(7) genitourinary abnormalities (hypospadias, cryptorchidism, hypoplastic or bifid scrotum)

(8) congenital heart defects

(9) imperforate or ectopic anus

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