J. Paediatr. Child Health (2005) 41, 380–381 Neonatal nasal obstruction and a single maxillary central incisor John Levison, 1 Katherine Neas, 2 Meredith Wilson, 2 Peter Cooper 3 and Julian Wojtulewicz 1 1 Grace Centre for Newborn Care, 2 Department of Clinical Genetics and 3 Respiratory Medicine, The Children’s Hospital at Westmead, Sydney, New South Wales, Australia Abstract: We present two neonates with nasal obstruction because of anterior choanal stenosis (congenital nasal pyriform aperture stenosis). An associated single maxillary central incisor was also shown on computed tomography imaging in the neonatal period. These midline anomalies are recognized minimal manifestations (microforms) of holoprosencephaly. We describe their neonatal investigation, multidisciplinary management and clinical course. Key words: congenital nasal pyriform aperture stenosis; holoprosencephaly; single maxillary central incisor. Although choanal atresia is the commonest bony cause of con- genital nasal obstruction, stenosis anteriorly at the bony inlet of the nose, the nasal pyriform aperture (congenital nasal pyriform aperture stenosis; CNPAS) is now increasingly recognized. 1 Congenital nasal pyriform aperture stenosis can occur as a mi- croform of the holoprosencephaly (HPE) spectrum, either as an isolated finding or with other radiological features of HPE, in- cluding a single maxillary central incisor (SMCI). It is important to recognize the significance of this association, as there are im- plications for further neonatal investigations and later prognosis, as well as family genetic counselling. We describe two cases of CNPAS associated with an SMCI shown by computed tomography (CT) imaging in the neonatal period. The family history in case 1 shows the extreme clinical variability possible in familial HPE spectrum disorders. This illustrates the importance of detailed clinical and genetic assess- ment of all such infants and their extended families. CASE 1 A term male infant, the eighth child of healthy unrelated parents, was admitted at 2 weeks of age with respiratory distress and nasal obstruction. At birth the infant’s head circumference was 34 cm (40th centile), length 48 cm (40th centile) and weight 3060 g (25th centile). On examination he had measurable hypotelorism and an absent upper labial frenulum. He had noisy nasal breathing. A size 5 Fr gauge catheter was passed nasally but with difficulty. An axial CT scan of the midface showed CNPAS (Fig. 1) and an SMCI. A cranial magnetic resonance imaging (MRI) scan showed the SMCI (Fig. 2) with normal brain anatomy, includ- ing demonstration of the pituitary gland. A karyotype, baseline pituitary hormone and glucose tests, and ophthalmic assessment were normal. The nasal obstruction improved transiently with topical steroid drops and he was discharged home. The infant was admitted to the paediatric intensive care at 1 month of age with viral bronchiolitis and increased nasal ob- struction. Surgical enlargement of the bony nasal aperture, via a sublabial approach, was performed at 4 months of age for con- tinued feeding difficulties. Growth and development was normal at 6 months of age. A female sibling was previously diagnosed with bilateral choanal stenosis at 4 months of age. An SMCI was seen on primary tooth eruption at 8 months of age. At 1 year of age she had microcephaly and moderate developmental delay, but Correspondence: Dr John Levison, Department of Newborn Care, Locked Bag 7103, Liverpool BC, NSW 1871, Australia. Fax: +61 2 9828 5582; email: john.levison@swsahs.nsw.gov.au Accepted for publication 4 March 2005. Fig. 1 Axial nasal CT scan. Narrow funnel-shaped nasal passage. An- teriorly, narrowed pyriform aperture. normal stature. Cranial imaging was not performed. She was recognized to have a form of HPE spectrum, but as no other family history was offered, an empirical recurrence risk of 6% was given. Further exploration of the family history revealed that her clinically normal father had also suffered severe nasal obstruction in infancy and that there were several other relatives with developmental delay and other features consistent with HPE spectrum, previously unrecognized. The family pedigree suggested an autosomal dominant form of HPE, with extremely variable expression. CASE 2 A term female infant, the fourth child of healthy unrelated par- ents, was admitted on day 1 of life with nasal obstruction and respiratory distress. Her birth head circumference was 34 cm (25th centile), weight 3420 g (45th centile) and length 48 cm (20th centile). She was not hypoteloric but had an absent upper labial frenulum. A 5 Fr gauge catheter was passed nasally with