Interstitial deletion of chromosome 13: prognosis and adult phenotype

Tall stature and minor facial dysmorphisms in a patient with a 17.5 Mb interstitial deletion of chromosome 13 (q14.3q21.33): clinical report and review

We present a 4-year-old boy with developmental delay and several into minor dysmorphic features due to an interstitial deletion of 17.5 Mb on the long arm of chromosome 13 [46,XY,del (13)(q14.3q21.33)]. The deletion was detected initially during routine cytogenetic screening and further analyzed on a genome-wide BAC array. In contrast to several previous papers reporting a short stature, our patient was tall with a 1 year advanced skeletal age. In this paper, we compare growth and clinical features of this patient with previously reported cases, with a similar interstitial deletion on the long arm of chromosome 13.

Application of ROMA (representational oligonucleotide microarray analysis) to patients with cytogenetic rearrangements

PURPOSE

To demonstrate the accuracy and sensitivity of Representational Oligonucleotide Microarray Analysis (ROMA) to describe copy number changes in patients with chromosomal abnormalities.

METHODS

ROMA was performed using BglII digested DNA from two cases with cytogenetically detected deletions and one case with an unbalanced terminal rearrangement detected only by subtelomeric FISH. Hybridization was to an 85,000-probe oligonucleotide microarray, providing an average resolution of 35 kb. FISH was used to confirm some of the ROMA findings.

RESULTS

By ROMA, a del(13)(q14.3q21.2) was shown to be noncontiguous, with deletions extending from 53.08 to 61.40 Mb and from 72.88 to 74.83 Mb. The 10-Mb deletion contained only six known genes. FISH confirmed the noncontiguous nature of the deletion, as well as a small amplification in 6q that was also found in the patient's mother. A del(4)(q12q21.2) was found by ROMA to be 23 Mb in length, from 58.8 to 81.9 Mb on chromosome 4, in agreement with the cytogenetically assigned breakpoints. ROMA showed that an unbalanced "subtelomeric" rearrangement involved a 6-Mb deletion of 22q and an 8-Mb duplication of 16q.

CONCLUSIONS

ROMA can define cytogenetic aberrations with extraordinary precision. Unexpected findings included the interrupted nature of the deletion in 13q and the large size of the imbalances in the "subtelomeric" rearrangement. Together with the information from the human genome sequence and proteomics, the ability to define rearrangements with "ultra-high" resolution will improve the ability to provide accurate prognosis both prenatally and postnatally to parents of offspring with chromosomal aberrations.

Distal 13q Deletion Syndrome and the VACTERL association: case report, literature review, and possible implications

We present a case of a child with del(13) (q31.1qter), VACTERL association, and penoscrotal transposition. Deletion of the distal long arm of chromosome 13 is associated with variable phenotypes. These phenotypes are divided into three clusters; each cluster represents a specific deleted segment of 13q. Individuals with deletions of a critical region at 13q32 have multiple congenital malformations that include components of the VACTERL association. Our patient had all six manifestations of VACTERL association. In addition, he had complete penoscrotal transposition, a unique malformation reported rarely in VACTERL association and only twice previously in deletion of distal 13q. We reviewed all reported cases of distal 13q deletions to date. Of these 137 patients, 15 could be classified into the VACTERL association. Ours was the only patient with distal 13q deletion and all VACTERL association features and also the only one with tracheoesophageal fistula. Neither holoprosencephaly nor the other central nervous system malformations that have been seen in individuals with distal 13q deletions were apparent in him. The patient presented here appears to be unique among individuals with distal 13q deletion. His cluster of malformations strengthens the argument that distal 13q deletion is a cause for VACTERL association, and that this causal relationship implies a syndromic form of VACTERL. In addition, this case and those ascertained from the literature suggest that penoscrotal transposition should be considered part of both the distal 13q-deletion syndrome and some forms of VACTERL association.