Autosomal recessive transmitted disease resulting in
death in the first year of life secondary to neurologic disease and airway
Approximately 43 cases have been reported in the literature.
39 of them were Hutterite patients and 4 were from other populations. The estimated incidence
in the Hutterite population is 1:355 live births.
Autosomal recessive trait. Comprehensive pedigree records have
enabled researchers to determine that all six of the Hutterite families are related
to a kindred extending back to the 1770s. The Hutterites subdivided into
three Leute groups after arriving in North America in the late 1800s. Cases
recognized from colonies in northern and southern Alberta, South Dakota, and
southern Manitoba suggest the gene for this condition may be widely
distributed among this population. Consanguinity was present within this
pedigree. The gene locus has been mapped to 12p13.3.
The gene responsible for this syndrome and the
underlying pathophysiology has not been determined. The exact cause of
death in these neonates remains unclear, but the combination of severe
neurologic impairment and airway abnormalities has been implicated.
Clinical course, physical appearance, and familial
history. Bowen-Conradi syndrome is morphologically very similar to trisomy
18, however, chromosome analysis is normal in the former.
Major features are proportional intrauterine
growth retardation and low birth weight, microcephaly, dolichocephaly, sloping forehead,
severe micrognathia, retroglossia, narrow pharynx, prominent nose,
rocker-bottom feet, mild joint movement limitations, and undescended testes. Neonates
with this condition have a significant neurologic deficit with poor muscle tone,
feeding, and crying, and developmental delay. The average age at death is 13 months
(range 1 day to 9 years).
Obtain a full clinical assessment of the
airway (micrognathia, retroglossia, narrow pharynx), the degree of neurologic
impairment (hypotonia, feeding difficulties, aspiration, impairment of
pharyngeal and laryngeal reflexes), the respiratory system (pneumonia,
hypoventilation secondary to hypotonia, sleep apnea or obstructive
episodes), and nutritional status. Laboratory investigations should include a
complete blood count, urea and electrolytes, and arterial blood gases
(indicator of pulmonary function).
Difficult direct laryngoscopy and
tracheal intubation should be anticipated in all cases. All the necessary
adjuncts for management of the difficult airway should be prepared before
induction of anesthesia. Inhalational induction with spontaneous respiration
prior to tracheal intubation or an awake fiberoptic intubation technique are the safest
approaches. In extreme instances, a tracheostomy may be required prior to
surgery. Use of regional anesthesia techniques is not specifically
contraindicated and will decrease the need for opioids with their
respiratory depressant side effects. A postoperative period of elective mechanical
ventilation may be necessary because of hypotonia, abnormal ventilatory
control, and poor respiratory function. After tracheal extubation, patients
will require continued cardiovascular, respiratory, and neurologic
monitoring in a high-dependency area because of the risk of apnea and airway
Care should be taken when
administering sedative, inhalational, opioid, or muscle-relaxing drugs
because these children are highly sensitive ...