OMIM ID:
Pigmentary Retinopathy with Congenital Sideroblastic Anemia
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
The ocular phenotype has not been fully described, but several patients with a pigmentary retinopathy resembling retinitis pigmentosa have been reported.
Systemic Features
Patients present at a median age of two months with typically severe microcytic sideroblastic anemia. Median hemoglobin levels are 7.1 g/dl. Lymphopenia and panhypogammaglobulinemia are usually present and many children have periodic febrile illnesses. The number of CD19+ B cells is reduced. Aminoaciduria, hypercalcinuria, and nephrocalcinosis have been observed. Cardiomyopathy has been seen in several patients and may be responsible for the early demise. Developmental delays may be severe with variable neurodegeneration features such as seizures, cerebellar symptoms, and sensorineural hearing loss. Achievement of milestones is generally delayed. Median survival is 4 years although one patient has lived to the age of 19 years.
Genetics
Inheritance
Homozygous mutations in TRNT1 (3p25.1) are responsible for this disorder.
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.