Xq22.3q23 microdeletion harboring TMEM164 and AMMECR1 genes: Two case reports confirming a recognizable phenotype with short stature, midface hypoplasia, intellectual delay, and elliptocytosis

Am J Med Genet A. 2019 Apr;179(4):650-654. doi: 10.1002/ajmg.a.61057. Epub 2019 Feb 8.

Abstract

The AMME syndrome defined as the combination of Alport syndrome, intellectual disability, midface hypoplasia, and elliptocytosis (AMME) is known to be a contiguous gene syndrome associated with microdeletions in the region Xq22.3q23. Recently, using exome sequencing, missense pathogenic variants in AMMECR1 have been associated with intellectual disability, midface hypoplasia, and elliptocytosis. In these cases, AMMECR1 gene appears to be responsible for most of the clinical features of the AMME syndrome except for Alport syndrome. In this article, we present two unrelated male patients with short stature, mild intellectual disability or neurodevelopmental delay, sensorineural hearing loss, and elliptocytosis harboring small microdeletions identified by array-CGH involving TMEM164 and AMMECR1 genes and SNORD96B small nucleolar RNA for one patient, inherited from their mothers. These original cases further confirm that most specific AMME features are ascribed to AMMECR1 haploinsufficiency. These cases reporting the smallest microdeletions encompassing AMMECR1 gene provide new evidence for involvement of AMMECR1 in the AMME phenotype and permit to discuss a phenotype related to AMMECR1 haploinsufficiency: developmental delay/intellectual deficiency, midface hypoplasia, midline defect, deafness, and short stature.

Keywords: AMMECR1; AMME syndrome; Xq22.3q23 deletions; array-CGH; elliptocytosis; hearing loss.

Publication types

  • Case Reports

MeSH terms

  • Child
  • Chromosome Deletion*
  • Chromosomes, Human, X / genetics*
  • Craniofacial Abnormalities / genetics*
  • Craniofacial Abnormalities / pathology*
  • Elliptocytosis, Hereditary / genetics*
  • Elliptocytosis, Hereditary / pathology*
  • Genetic Diseases, X-Linked / genetics*
  • Genetic Diseases, X-Linked / pathology*
  • Humans
  • Intellectual Disability / genetics*
  • Intellectual Disability / pathology*
  • Male
  • Membrane Proteins / genetics*
  • Nephritis, Hereditary / genetics*
  • Nephritis, Hereditary / pathology*
  • Prognosis
  • Proteins / genetics*

Substances

  • AMMECR1 protein, human
  • Membrane Proteins
  • Proteins

Supplementary concepts

  • Alport Syndrome, Mental Retardation, Midface Hypoplasia, and Elliptocytosis