PIGN
Name of Disorder

PIGN-congenital disorder of glycosylation (PIGN-CDG, also known as Multiple Congenital Anomalies-Hypotonia-Seizures Syndrome 1). It belongs to a group of disorders called Glycosylphosphatidylinositol (GPI-) anchor defects.

Symptoms

PIGT-CDG is a very rare inherited condition that affects multiple parts of the body and causes multiple congenital anomalies. Affected individuals typically develop signs and symptoms of the condition during infancy. Individuals with PIGN-CDG universally have severe developmental delay, hypotonia, and seizures. They frequently have abnormal facial features, underdeveloped fingertips, GI reflux, cerebellar atrophy, small corpus callosum, cerebral volume loss, abnormal or delayed myelination, and may require feeding tubes. They occasionally have congenital heart disease, renal anomalies (including renal dysplasia and cortical cysts), hepatosplenomegaly, scoliosis, and abnormal movements (choreoathetosis, extrapyramidal dyskinesia). There is a large clinical spectrum associated with PIGN-CDG, with the most severe being intrauterine death due to congenital anomalies. Those who are mildly affected may have isolated developmental delay and intellectual disability.

Diagnosis

The primary screening tool for PIGN-CDG is testing for the presence of GPI-anchored proteins on the surface of granulocytes (a subset of white blood cells). This can be tested by a method called flow cytometry in the patient’s blood. The ultimate diagnosis is genetic testing in blood. Individuals with PIGN-CDG have two faulty copies of the PIGN gene.

Treatment and prognosis

To date, there are no known specific treatment options for PIGN-CDG. Treatment is aimed at the management of symptoms and the prevention of complications. Most diagnosed PIGN-CDG patients are still young, which makes long-term prognosis difficult.