Renpenning Syndrome 1: PQBP1 Gene Deletion/Duplication

Condition Description

Mutationsin the PQBP1 gene (Xp11.23) causeX-linked recessive mental retardation that is often syndromic but can benonsyndromic. PQBP1 mutations havebeen associated with Renpenning syndrome, Sutherland-Hann syndrome, cerebropalatocardiac(Hamel) syndrome, and Golabi-Ito-Hall syndrome. Common features of X-linkedmental retardation caused by PQBP1mutation seem to be mental retardation, microcephaly, and short stature. Considerablephenotypic variability is observed between families with different mutationsand even between families with the same mutation.

Inaddition to mental retardation, microcephaly, and short stature, other reportedfeatures include small testes, ocular colobomas, cardiac malformations, cleftpalate, spastic diplegia, and anal anomalies. Facial characteristics includenarrow and tall craniofacies with upslanting palpebral fissures, abnormal nasalconfiguration, cupped ears, and short philtrum. The nose may appear long orbulbous, with overhanging columella.

Historically, Renpenning syndromehas been associated with mental retardation with short stature, moderatemicrocephaly, but no remarkable facies and no other neurologic abnormalities.Sutherland-Haan syndrome has been associated with mental retardation, shortstature, microcephaly, brachycephaly, spastic diplegia, small testes, andpossibly intrauterine growth retardation. Cerebropalatocardiac (Hamel) syndromehas been associated with severe mental retardation with congenital heart defects,microcephaly, spasticity, short stature, cleft or highly arched palate, andother craniofacial abnormalities. Golabi-Ito-Hall syndrome has been associatedwith mental retardation, microcephaly, postnatal growth deficiency, and otheranomalies, including atrial septal defect.

Click here for the OMIM summary on this condition.

Genes (1)

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Indications

This test is indicated for:

  • Confirmation of a clinical/biochemical diagnosis of Renpenning syndrome in individuals who have tested negative for sequence analysis
  • Carrier testing in adult females with a family history of Renpenning syndrome who have tested negative for sequence analysis

Methodology

DNA isolated from peripheral blood is hybridized to a CGH array to detect deletions and duplications. The targeted CGH array has overlapping probes which cover the entire genomic region.

Detection

Detection is limited to duplications and deletions. The CGH array will not detect point or intronic mutations. Results of molecular analysis must be interpreted in the context of the patient's clinical and/or biochemical phenotype.

Specimen Requirements

When sample fails to meet the acceptable criteria, please call 470.378.2200 and ask to speak with a laboratory genetic counselor (eglgc@egl-eurofins.com).
Submit only 1 of the following specimen types
DNA, Isolated
DNA

Requirements
Microtainer
3µg
Isolation using the Perkin Elmer™Chemagen™ Chemagen™ Automated Extraction method or Qiagen™ Puregene kit for DNA extraction is recommended.
Collection and Shipping
Refrigerate until time of shipment in 100 ng/µL in TE buffer. Ship sample at room temperature with overnight delivery.
Whole Blood (EDTA)
WBP

Requirements
EDTA (Purple Top)
Infants and Young Children (<2 years of age): 2-3 ml
Children > 2 years of age to 10 years old: 3-5 ml
Older Children & Adults: 5-10 ml
Autopsy: 2-3 ml unclotted cord or cardiac blood
Collection and Shipping
Ship sample at room temperature for receipt at EGL within 24 hours of collection. Do not refrigerate or freeze.

Special Instructions

Submit copies of diagnostic biochemical test results with the sample, if appropriate. Contact the laboratory if further information is needed.

Sequence analysis is required before deletion/duplication analysis by targeted CGH array. If sequencing is performed outside of EGL Genetics, please submit a copy of the sequencing report with the test requisition.

  • Sequencing analysis of the PQBP1 gene is available (YP) and is required before deletion/duplication analysis.
  • ACGH array-based test for deletion/duplication analysis of 64 differentX-linked intellectual disability genes is available (OL).
  • Prenataltesting is available to adult females who are confirmed carriers ofmutations. Please contact the laboratory genetic counselor to discussappropriate testing prior to collecting a prenatal specimen.

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