Gene: FGFR1 (fibroblast growth factor receptor-1)
Gene location: 8p12
Inheritance: autosomal dominant with incomplete penetrance (parents and other family members often affected), However, almost a third of patients may have a de novo mutation.
Clinical features:
(1) variable loss of smell (no loss to anosmia)
(2) variable hypogonadism
(3) variable cleft palate
(4) tooth agenesis
(5) variable hearing impairment
(6) agenesis of the corpus callosum
(7) hypoplasia of the external ear
(8) absence of nasal cartilage
(9) bone anomalies in the hands and feet
(10) iris coloboma
Findings suggesting KAL1 (see previous section):
(1) bimanual synkinesis
(2) renal agenesis
Findings suggesting involvement of contiguous genes:
(1) severe anemia (involvement of ANK1)
(2) blindness (deletion at 8p11.2-12)
