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The paper described selected morphological and developmental features associated with subtelomeric deletion …

Biology Articles » Anatomy & Physiology » Anatomy, Human » Further phenotypic delineation of subtelomeric (terminal) 4q deletion with emphasis on intracranial and reproductive anatomy » Discussion

- Further phenotypic delineation of subtelomeric (terminal) 4q deletion with emphasis on intracranial and reproductive anatomy

Deletions at 4q have been associated with multiple abnormal physical findings including dysmorphic skull, hypertelorism, cleft palate, short nose with abnormal bridge, and hypoplastic distal phalanx of fifth finger with hooked/volar nail [1,3-5]. The latter of these features has been suggested as virtually pathognomonic for deletion at 4q34 [1]. Interestingly, a small interstitial deletion at 4q31 has been proposed as the "minimal critical region" most likely responsible for the 4q syndrome [6]. The impact of 4q deletion on reproductive and intracranial anatomy remains unknown, however.

That reproductive organs might be adversely impacted by 4q deletion appeared plausible since discontinuous 4q deletions have been implicated in squamous cell and adenocarcinoma of the cervix. Sherwood et al concluded that loss at "any chromosome 4 locus occurred in 92% of all (cervical) tumors studied, with the majority of deletions occurring on the long arm of this chromosome" [7]. While further studies to identify specific oncogenes in this chromosomal region continue, for our patient emphasis on tobacco avoidance and routine cervical cancer surveillance via cytology are particularly relevant. While no major deviation from normal was evident regarding uterine and adnexal anatomy, the bilateral fibroadipose aggregates flanking the uterus in the space between the fallopian tube and round ligament represent, to our knowledge, a previously undescribed phenotypic finding for this genetic disorder. Similarly, the observed calcified peritoneal punctations without endometriosis may represent an additional connective tissue derangement of undetermined significance.

The 4q deletion sequence can include mild mental retardation [4,5] and our patient did demonstrate reduced intellectual function and cognitive impairment. While no gross intracranial pathology was identified in this case, high resolution imaging of brain parenchyma did reveal a region of abnormal density, initially thought to be an arteriovenous malformation. Given the well-recognized connective tissue abnormalities seen in 4q deletion, additional imaging modalities were deployed with reassuring results. In the setting of a stable, non-focal neurological examination with no reported seizure activity or head trauma, the intracranial lesion observed in our patient may represent merely an old lacunar infarct rather than a morphological variant directly related to 4q deletion. Unfortunately previous brain imaging studies were not available for comparison, and periodic reassessment was advised.

While the present report describes new morphological features associated with a 4q32 terminal deletion, continued observational studies are needed to show how deletion of genetic material at this locus impacts development.

Competing interests

The author(s) declare that they have no competing interests.

Authors' contributions

ESS, MJB, LDP, LPC, LLK, CSD, PRP and JGD all contributed equally to develop and edit the article. ESS was principal physician and coordinated the research and JGD was senior geneticist; PRP directed the genetics laboratory analyses.

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