On this page, you will find information about a genetic change that was identified in a UDN participant. 

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Date of Report

Nov 18, 2016

Full Name

Solute carrier family 35 member A2

Chromosome X (Xp11.23)


The SLC35A2 gene codes for a nucleotide sugar transporter that is important in the glycosylation process (Maszczak-Seneczko et al., 2015).

Database Links

GeneCards: GC0XM048903

Genetics Home Reference: SLC35A2 gene

NCBI Gene: 7355

OMIM: 314375

UniProtKB/Swiss-Prot: P78381

Clinical Significance

Changes in the SLC35A2 gene have been found in individuals with congenital disorder of glycosylation, type IIm.

A change in the SLC35A2 gene was identified in a UDN participant with features of this condition.

The participant, a 2 year old female, was found to carry the following genetic change in the SLC35A2 gene: c.245G>T/p.C82F.

Gene SLC35A2
Inheritance Pattern X-linked
Position ChrX:48767120
Transcript NM_005660
DNA Change c.245G>T Participant is 15.5% mosaic for this variant
Protein Change p.C82F

Shortly after birth, the patient was found to have pyloric stenosis, a condition in which muscles block food from entering the small intestine. She underwent surgery to correct this at 9 weeks. Currently she has reduced functioning of her stomach and intestines (reduced gastric and intestinal motility) and constipation. She has had trouble gaining weight.

At 3 months, the patient was diagnosed with infantile spasms, which have not been controlled with medication. A brain MRI showed a decrease of white matter and vermis in the brain (progressive diffuse atrophy of the hemispheric white matter and vermis). Her left leg is also bigger and longer than her right leg (hemi-hypertrophy of left leg).

Developmentally, the patient has stopped gaining milestones, but has not regressed. She often has difficulty sleeping through the night.

Some of her other features include:

  • Short stature
  • Decreased bone density (osteopenia)
  • Reduced amount of homovanillic acid in cerebrospinal fluid (decreased CSF homovanillic acid)
  • Reduced amount of creatinine, alkaline phosphatase, and albumin in blood (decreased serum creatinine, low alkaline phosphatase, hypoalbuminemia)
  • Increased testosterone hormone and immunoglobulin M in blood (increased serum testosterone level, IgM level)
  • Large red blood cells (erythrocyte macrocytosis)
  • Increased amount of red blood cells (increased hematocrit)
  • Increased number of white blood cells called monocytes (monocytosis)
  • Decreased number of white blood cells called neutrophils (neutropenia)
  • Low blood sugar (hypoglycemia)
  • Seizures (infantile spasms)
  • Abnormal EEG (hypsarrhythmia)
  • Narrow forehead
  • Low hairline at the back of the head (posterior)
  • Vision loss caused by damage to the visual cortex (cortical visual impairment)
  • Farsightedness (hypermetropia)
  • Whites of the eyes appear blue (blue sclerae)
  • Colored splotches on the eye (retinal pigment epithelial mottling)
  • Eyes turned inward/crossed eye (esotropia)
  • High palate
  • Central and obstructive sleep apnea
  • Low muscle tone (muscular hypotonia)
  • Abnormal intestinal contractions (hypoperistalsis)
  • Acid reflux/heartburn (gastroesophageal reflux)
  • Constipation
  • Anus located closer to genitals (anteriorly placed anus)
  • Early sexual maturation (premature adrenarche)
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