Prenatal diagnosis of episodic tachypnea in an infant with OFD VI.
Episodic tachypnea is a typical neonatal presentation of Joubert syndrome, but may also occur in infants with other anomalies of the cerebellar vermis. Even though fetuses at risk for Joubert syndrome are usually closely followed by ultrasound, this respiratory pattern has only once been described prenatally. We describe a patient who presented prenatally with posterior meningocele, Dandy-Walker cyst, and four limb polydactyly on ultrasound. Amniocentesis showed a normal male karyotype and normal 7DHC. At 31 weeks, episodic fetal tachypnea was noted on ultrasound. The working diagnosis was Joubert syndrome or oro-facio-digital syndrome type VI (OFD VI). At birth, in addition to the findings noted prenatally, he had multiple nodules of his tongue, a Y-shaped metacarpal and micropenis. His respiratory pattern was notable for alternating tachypnea and apnea with respiratory rates up to 200 followed by apnea and bradycardia. Magnetic resonance image showed Dandy-Walker with massive 4th ventricle, complete absence of the cerebellar vermis, hypoplastic brainstem, and small meningocele. Development is profoundly delayed and he remains ventilator dependent. Both the previously described Joubert patient with prenatally recognized tachypnea, and our patient are atypical for Joubert syndrome since they have polydactyly (which occurs in only 8% of Joubert patients) and hamartomas of the tongue (which occur in 2%). Despite the tongue hamartomas, these patients are not entirely typical for OFD VI, since their polydactyly is postaxial. The observation of prenatal tachypnea in these two patients, but not in typical Joubert patients, suggests they have either a variant of OFD VI or a new Joubert or OFD-like syndrome.