Diagnostic Criteria

Suggestive Findings

SLC39A8-CDG should be suspected in probands with the following clinical, laboratory, imaging, and family history findings.

Clinical findings

• Mild-to-profound developmental delay and/or intellectual disability

• Generalized hypotonia of infancy

• Feeding difficulties with poor weight gain and growth deficiency

• Movement disorder with marked dystonia

• Spasticity

• Epilepsy, especially severe infantile epileptic spasms not responding to conventional treatment

• Ophthalmologic manifestations including cortical blindness and strabismus

• Sensorineural hearing impairment

Laboratory findings

Source: GeneReviews — "SLC39A8-CDG"

Differential Diagnosis

Early infantile presentation (in those infants who have not yet had an MRI). Many metabolic and genetic disorders that present in infancy share at least some of the clinical features of SLC39A8-CDG. Metabolic disorders in the differential diagnosis of hypotonia, developmental delay, and growth deficiency are summarized in . Table 3a. Metabolic Disorders to Consider in the Differential Diagnosis of SLC39A8-CDG in Infants Who Have Not Yet Had an MRI

Management Guidelines

No clinical practice guidelines for SLC39A8-CDG have been published. Evaluations Following Initial Diagnosis To establish the extent of disease and needs in an individual diagnosed with SLC39A8-CDG, the evaluations summarized (if not performed as part of the evaluation that led to the diagnosis) are recommended. Table 4. Recommended Evaluations Following Initial Diagnosis in Individuals with SLC39A8-CDG

Source: GeneReviews — "SLC39A8-CDG"

Clinical Guidance

Fever. It is well established that increases in body temperature are associated with further impairment of the residual glycosylation in congenital disorders of glycosylation. Therefore, antipyretic treatment to reduce and/or prevent fever is recommended. Hepatotoxic drugs. In those with evidence of liver dysfunction, hepatotoxic agents should be avoided or used with extreme caution. Drugs contraindicated in mitochondriopathies. Due to secondary impairment of mitochondrial function, agents contraindicated in mitochondriopathies (e.g., valproate) should be avoided in individuals with SLC39A8-CDG.

Source: GeneReviews — "SLC39A8-CDG"

Surveillance Guidelines

To monitor existing manifestations, the individual's response to supportive care, and the emergence of new manifestations, the evaluations summarized in are recommended. Table 6. Recommended Surveillance for Individuals with SLC39A8-CDG

Source: GeneReviews — "SLC39A8-CDG"