2q23.1 Microdeletion Syndrome and Autism Spectrum Disorder via the MBD5 Gene
Summary and Pricing 
Test Method
Sequencing and CNV Detection via NextGen Sequencing using PG-Select Capture Probes
| Test Code | Test Copy Genes | Test CPT Code | Gene CPT Codes Copy CPT Code | Base Price | |
|---|---|---|---|---|---|
| 4183 | MBD5 | 81479 | 81479,81479 | $990 | Order Options and Pricing |
Pricing Comments
Testing run on PG-select capture probes includes CNV analysis for the gene(s) on the panel but does not permit the optional add on of exome-wide CNV analysis. Any of the NGS platforms allow reflex to other clinically relevant genes, up to whole exome or whole genome sequencing depending upon the base platform selected for the initial test.
An additional 25% charge will be applied to STAT orders. STAT orders are prioritized throughout the testing process.
This test is also offered via a custom panel (click here) on our exome or genome backbone which permits the optional add on of exome-wide CNV or genome-wide SV analysis.
Turnaround Time
3 weeks on average for standard orders or 2 weeks on average for STAT orders.
Please note: Once the testing process begins, an Estimated Report Date (ERD) range will be displayed in the portal. This is the most accurate prediction of when your report will be complete and may differ from the average TAT published on our website. About 85% of our tests will be reported within or before the ERD range. We will notify you of significant delays or holds which will impact the ERD. Learn more about turnaround times here.
Targeted Testing
For ordering sequencing of targeted known variants, go to our Targeted Variants page.
Clinical Features and Genetics
Clinical Features
Autosomal dominant intellectual disability via 2q23.1 microdeletion syndrome is a neurocognitive disorder characterized by moderate to severe intellectual disability and motor delay. 2q23.1 microdeletion syndrome patients often present in infancy with hypotonia and feeding difficulties. During childhood patients may develop seizures, stereotypic hand movements, sleep disturbances, short attention span and autistic-like behaviors (Talkowski et al. 2011). 2q23.1 microdeletion syndrome patients exhibit severe language impairment, often not being able to speak meaningful words. Physical features of patients with 2q23.1 microdeletion syndrome include thick arched eyebrows, broad forehead, downturned mouth and thin upper lip (Hodge et al. 2013).
Gross deletions of the 2q23.1 region results in a more severe clinical phenotype than variations that affect only the MBD5 gene, suggesting other genes in the deletion interval contribute to the phenotype. Additional features seen in large 2q23.1 deletion cases include an ataxic gait, self-injurious behaviors, hyperphagia and obesity, pinnae abnormalities, microcephaly and short fifth digit of hands and feet (Talkowski et al. 2011).
2q23.1 microduplications have also been reported in patients with intellectual disability. The most common features of 2q23.1 microduplication syndrome are psychomotor delay, language impairment, infantile hypotonia, behavioral problems and autistic-like symptoms (Mullegama et al. 2013). Shared facial features observed in patients include downslanting palpebral fissures, arched eyebrows, long eyelashes, prominent nose and pinnae abnormalities.
Genetics
2q23.1 microdeletion syndrome is caused by deletions encompassing the MBD5 gene. 2q23.1 microdeletion syndrome is an autosomal dominant disorder and many cases are sporadic, resulting from de novo deletions encompassing the MBD5 gene. Causative nonsense and frameshift mutations in MBD5 have also been reported in patients with intellectual disability (Kleefstra et al. 2012; Bonnet et al. 2013). A number of missense variants in MBD5 have been reported in patients with intellectual disability or autism, but the causal nature of these variants is not yet clear (Wagenstaller et al. 2007; Cukier et al. 2012; Talkowski et al. 2011) MBD5 encodes a protein with a methyl-CpG binding domain that belongs to the same structural family as MeCP2. MBD5 localizes to heterochromatic regions of DNA around centromeres, but has not been shown to bind directly to methylated DNA (Laget et al. 2010). It is proposed that MBD5 directs epigenetic regulation of neuronal gene expression.
Clinical Sensitivity - Sequencing with CNV PG-Select
One study identified a de novo nonsense variant in MBD5 in 1 of 78 (~1%) individuals with moderate to severe intellectual disability of unknown cause (Bonnet et al. 2013).
Testing Strategy
This test provides full coverage of all coding exons of the MBD5 gene, plus ~10 bases of flanking noncoding DNA. We define full coverage as >20X NGS reads or Sanger sequencing.
Indications for Test
MBD5 testing should be considered in patients with clinical features of 2q23.1 deletion syndrome. In addition, MBD5 testing should be considered in patients diagnosed with Angelman, Rett, Smith-Magenis or other clinically overlapping syndromes but for which no genetic cause has been identified (Van Bon et al. 2009).
MBD5 testing should be considered in patients with clinical features of 2q23.1 deletion syndrome. In addition, MBD5 testing should be considered in patients diagnosed with Angelman, Rett, Smith-Magenis or other clinically overlapping syndromes but for which no genetic cause has been identified (Van Bon et al. 2009).
Gene
| Official Gene Symbol | OMIM ID |
|---|---|
| MBD5 | 611472 |
| Inheritance | Abbreviation |
|---|---|
| Autosomal Dominant | AD |
| Autosomal Recessive | AR |
| X-Linked | XL |
| Mitochondrial | MT |
Disease
| Name | Inheritance | OMIM ID |
|---|---|---|
| Mental Retardation, Autosomal Dominant 1 | AD | 156200 |
Citations
- Bon BW Van, Koolen DA, Brueton L, McMullan D, Lichtenbelt KD, Adès LC, Peters G, Gibson K, Novara F, Pramparo T. 2009. The 2q23. 1 microdeletion syndrome: clinical and behavioural phenotype. European journal of human genetics 18: 163–170. PubMed ID: 19809484
- Bonnet C, Khan A Ali, Bresso E, Vigouroux C, Béri M, Lejczak S, Deemer B, Andrieux J, Philippe C, Moncla A, Giurgea I, Devignes M-D, et al. 2013. Extended spectrum of MBD5 mutations in neurodevelopmental disorders. European Journal of Human Genetics. PubMed ID: 23422940
- Cukier HN, Lee JM, Ma D, Young JI, Mayo V, Butler BL, Ramsook SS, Rantus JA, Abrams AJ, Whitehead PL, Wright HH, Abramson RK, et al. 2012. The Expanding Role of MBD Genes in Autism: Identification of a MECP2 Duplication and Novel Alterations in MBD5 , MBD6 , and SETDB1: ASD patients with novel variants in MBD genes. Autism Research 5: 385–397. PubMed ID: 23055267
- Hodge JC, Mitchell E, Pillalamarri V, Toler TL, Bartel F, Kearney HM, Zou YS, Tan WH, Hanscom C, Kirmani S, Hanson RR, Skinner SA, et al. 2013. Disruption of MBD5 contributes to a spectrum of psychopathology and neurodevelopmental abnormalities. Molecular Psychiatry. PubMed ID: 23587880
- Kleefstra, T. et al. (2012). "Disruption of an EHMT1-Associated Chromatin-Modification Moduce Causes Intellectual Disability." Am J Hu Genet 91(1):73-82. PubMed ID: 22726846
- Laget S, Joulie M, Masson F Le, Sasai N, Christians E, Pradhan S, Roberts RJ, Defossez P-A. 2010. The Human Proteins MBD5 and MBD6 Associate with Heterochromatin but They Do Not Bind Methylated DNA. PLoS ONE 5: e11982. PubMed ID: 20700456
- Mullegama SV, Rosenfeld JA, Orellana C, Bon BWM van, Halbach S, Repnikova EA, Brick L, Li C, Dupuis L, Rosello M, Aradhya S, Stavropoulos DJ, et al. 2013. Reciprocal deletion and duplication at 2q23.1 indicates a role for MBD5 in autism spectrum disorder. European Journal of Human Genetics. PubMed ID: 23632792
- Talkowski ME, Mullegama SV, Rosenfeld JA, Bon BWM van, Shen Y, Repnikova EA, Gastier-Foster J, Thrush DL, Kathiresan S, Ruderfer DM, Chiang C, Hanscom C, et al. 2011. Assessment of 2q23.1 Microdeletion Syndrome Implicates MBD5 as a Single Causal Locus of Intellectual Disability, Epilepsy, and Autism Spectrum Disorder. The American Journal of Human Genetics 89: 551–563. PubMed ID: 21981781
- Wagenstaller J, Spranger S, Lorenz-Depiereux B, Kazmierczak B, Nathrath M, Wahl D, Heye B, Gläser D, Liebscher V, Meitinger T, Strom TM. 2007. Copy-Number Variations Measured by Single-Nucleotide–Polymorphism Oligonucleotide Arrays in Patients with Mental Retardation. The American Journal of Human Genetics 81: 768–779. PubMed ID: 17847001
Ordering/Specimens
Ordering Options
We offer several options when ordering sequencing tests. For more information on these options, see our Ordering Instructions page. To view available options, click on the Order Options button within the test description.
myPrevent - Online Ordering
- The test can be added to your online orders in the Summary and Pricing section.
- Once the test has been added log in to myPrevent to fill out an online requisition form.
- PGnome sequencing panels can be ordered via the myPrevent portal only at this time.
Requisition Form
- A completed requisition form must accompany all specimens.
- Billing information along with specimen and shipping instructions are within the requisition form.
- All testing must be ordered by a qualified healthcare provider.
For Requisition Forms, visit our Forms page
If ordering a Duo or Trio test, the proband and all comparator samples are required to initiate testing. If we do not receive all required samples for the test ordered within 21 days, we will convert the order to the most effective testing strategy with the samples available. Prior authorization and/or billing in place may be impacted by a change in test code.
Specimen Types
Specimen Requirements and Shipping Details
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