On this page, you will find information about a genetic change that was identified in a UDN participant. We are trying to find others with the same or similar condition. (Sharing information on this website is not a requirement of UDN participation. Only descriptions of participants who give explicit consent will appear here.)

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Date of Report November 18, 2016
Full Gene Name Solute carrier family 35 member A2
Location Chromosome X (Xp11.23)
Ideogram: SLC35A2 Gene on Chromosome X

Click to enlarge ideogram in new window (generated using the NCBI Genome Decoration Page )
Function The SLC35A2 gene codes for a guanine nucleotide exchange factor for RhoA GTPases (Maszczak-Seneczko et al., 2015 ).
Database Links GeneCards: GC0XM048903 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 also 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 Inheritance Pattern Position Transcript DNA Change Protein Change
SLC35A2 X-linked ChrX:48767120 NM_005660 c.245G>T
Participant is 15.5% mosaic for this variant
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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