OMIM ID:
Temtamy Syndrome
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
Bilateral chorioretinal colobomas may be present and involve the optic nerve in one-third of patients. Visual acuity is not measureable but significant vision impairment is evident in most patients and may be progressive in some individuals. Several have been reported with dislocated lenses, ptosis, microcornea, cataracts, microphthalmia, myopia, and posterior staphylomas.
Systemic Features
Mild, nonspecific craniofacial dysmorphism is often present. Some form of macrocephaly, with an elongated face, low-set ears, and micrognathia has been reported. Short stature is of the proportionate type. Significant developmental delay is evident during childhood and patients are nonverbal. A variety of cardiovascular anomalies such as septal defects, aortic dilation, and patent ductus arteriosus have been described. MRI shows mild hypoplasia of the corpus callosum. The gait may be ataxic and some (59%) individuals have spasticity of limb muscles with or without contractures. Seizures develop in early childhood, usually before the age of 3 years, and are difficult to control.
Genetics
Inheritance
The inconsistent and highly variable phenotype hints that this is a genetically heterogeneous condition. Many patients seem to have an autosomal recessive condition secondary to mutations in C12orf57 (12p13.31).
A syndrome consisting primarily of colobomas, ptosis, hypertelorism, and global delay (243310) has some similar clinical features but is caused by mutations in ACTG1.
Pedigree
Autosomal recessive
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.