This case report is of a 35-week female neonate with the finding of cystic abdominal mass on 28-week antenatal ultrasound, confirmed by fetal MRI and suspected to be hydrometrocolpos. At birth the infant’s physical exam was notable for post axial polydactyly (PAP) of left hand and right foot, distended abdomen with a circumference of 36cm, and abnormal urethral opening requiring suprapubic catheterization on day of life one. Chest x-ray reveals hypo-inflated lungs and abdominal ultrasound reveals bilateral hydronephrosis and pelvic ascites. The differential diagnosis includes Bardet-Biedl Syndrome (BBS) versus McKusick-Kaufman Syndrome (MKKS). Genetic panel revealed she was a carrier for a BBS genetic mutation. BBS is a rare autosomal recessive ciliopathy, which manifests as retinal degeneration/dystrophy, genital malformations, polydactyly, obesity, renal dysfunction, and cognitive impairments.
Genetic analysis alone cannot make the definitive diagnosis, as there is genetic overlap between BBS and MKKS. The neonatal presentation of hydrometrocolpos with PAP should raise clinical suspicion for either syndrome. Since definitive diagnosis is made based on clinical criteria which develop as the child ages, close clinical follow up and screening is imperative. Renal disease and retinal degeneration are two devastating sequelae of this syndrome, with ESRD developing by the age of 5 and legal blindness developing by the second to third decade of life.
Day, Morgan; Crystal Avila; and Dawn Novak. "Hydrometrocolpos and post-axial polydactyly in a neonate; A case presentation." (2021). https://digitalrepository.unm.edu/hsc_2021_pediatric_research/6