Also known as congenital disorder of glycosylation type In
A rare genetic condition caused by an abnormal protein disrupting N-linked glycosylation. Symptoms manifest during infancy, including seizures, low muscle tone (hypotonia), global developmental delay, sensorineural hearing loss, decreased visual acuity, and coagulation abnormalities.
Symptoms
RFT1-CDG is a rare autosomal recessive condition and currently only 16 cases have been reported in the medical literature. Signs and symptoms typically develop in infancy and affect different body systems. Individuals have infantile-onset seizures, low muscle tone (hypotonia), and global developmental delay. Most patients reported have had sensorineural hearing loss, decreased visual acuity, feeding difficulties, and failure to thrive. A few patients have been reported to have variable physical differences like microcephaly (a small head), micrognathia (a small, recessed chin), a short neck, and inverted nipples. Laboratory findings may show coagulopathy.
Four of the 16 patients reported in the literature presented more mildly, including two adult siblings with intellectual disability, well-controlled epilepsy, and hearing impairment, and two other individuals with mild developmental delay, behavioral problems, ataxia, and dysmorphism, without hearing loss of epilepsy.
Diagnosis
The primary screening tool is testing of the appropriate glycosylation of common proteins (most commonly, transferrin), in blood. The ultimate diagnosis is made by genetic testing in blood. Individuals with RFT1-CDG have two non-working copies of the RFT-1 gene.
Treatment and prognosis
Currently, there are no curative treatments available for RFT1-CDG. Treatment is aimed at easing and alleviating the symptoms experienced by the patient (symptomatic treatment). In RFT1-CDG, this often includes controlling a patient’s seizures with medication, receiving therapies to help with development, and being evaluated by an audiologist for hearing loss.