Temple-Baraitser syndrome, previously described in two unrelated patients, is the association of severe mental retardation and abnormal thumbs and great toes. We report two additional unrelated patients with Temple-Baraitser syndrome, review clinical and radiological features of previously reported cases and discuss mode of inheritance. Patients share a consistent pattern of anomalies: hypo or aplasia of the thumb and great toe nails and broadening and/or elongation of the thumbs and halluces, which have a tubular aspect. All patients were born to unrelated parents and occurred as a single occurrence in multiple sibships, suggesting sporadic inheritance from a de novo mutation mechanism. Comparative genomic hybridization in Patients 1, 2 and 3 did not reveal any copy number variations. We confirm that Temple-Baraitser syndrome represents a distinct syndrome, probably unrecognized, possibly caused by a de novo mutation in a not yet identified gene.
Temple and Baraitser (1991) reported a 3.5-year-old boy, born of
nonconsanguineous Iranian parents, with a severe mental retardation
syndrome characterized by hypotonia, seizures, and generalized cerebral
atrophy. He had a low frontal hairline with central cowlick, mild
hypertelorism, ptosis, and a prominent nose. Skeletal features included
small hypoplastic thumb nails and absent great toe nails. Radiographs
showed central lucent areas in the distal phalanges of both thumbs
resembling pseudoepiphyses. The terminal phalanges of other digits on
both hands and feet were hypoplastic.
Gabbett et al. (2008) reported a 4-year-old boy with a similar phenotype
to that reported by Temple and Baraitser (1991). He had marked
hypotonia, global developmental delay, and seizures. Other features
included myopathic facies with flat forehead, broad depressed nasal
bridge, epicanthal folds, short columella, long philtrum, broad mouth
with downturned corners, and high-arched palate. Both thumbs were
terminally broad with hypoplasia of the nail. The halluces were long and
broad with nail aplasia bilaterally. Radiographs showed pseudoepiphyses
of the thumbs and hypoplasia of all other terminal phalanges. Gabbett et
al. (2008) noted that the patient's mother had a seizure disorder and
took carbamazepine during pregnancy, which may have accounted for some
of the facial dysmorphism. Both Temple and Baraitser (1991) and Gabbett
et al. (2008) noted some phenotypic similarities to DOOR syndrome
(220500), but neither patient had deafness.
nonconsanguineous Iranian parents, with a severe mental retardation
syndrome characterized by hypotonia, seizures, and generalized cerebral
atrophy. He had a low frontal hairline with central cowlick, mild
hypertelorism, ptosis, and a prominent nose. Skeletal features included
small hypoplastic thumb nails and absent great toe nails. Radiographs
showed central lucent areas in the distal phalanges of both thumbs
resembling pseudoepiphyses. The terminal phalanges of other digits on
both hands and feet were hypoplastic.
Gabbett et al. (2008) reported a 4-year-old boy with a similar phenotype
to that reported by Temple and Baraitser (1991). He had marked
hypotonia, global developmental delay, and seizures. Other features
included myopathic facies with flat forehead, broad depressed nasal
bridge, epicanthal folds, short columella, long philtrum, broad mouth
with downturned corners, and high-arched palate. Both thumbs were
terminally broad with hypoplasia of the nail. The halluces were long and
broad with nail aplasia bilaterally. Radiographs showed pseudoepiphyses
of the thumbs and hypoplasia of all other terminal phalanges. Gabbett et
al. (2008) noted that the patient's mother had a seizure disorder and
took carbamazepine during pregnancy, which may have accounted for some
of the facial dysmorphism. Both Temple and Baraitser (1991) and Gabbett
et al. (2008) noted some phenotypic similarities to DOOR syndrome
(220500), but neither patient had deafness.
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