Clinical, cytogenetic and molecular investigations in three patients with Wolf-Hirschhorn syndrome

Wolf-Hirschhorn syndrome: Prenatal diagnosis and molecular cytogenetic characterization of a de novo distal deletion of 4p (4p16.1 → pter) in a fetus with facial cleft and preaxial polydactyly

OBJECTIVE

We present prenatal diagnosis and molecular cytogenetic characterization of Wolf-Hirschhorn syndrome (WHS) in a fetus with facial cleft and preaxial polydactyly.

MATERIALS AND METHODS

A 37-year-old woman underwent amniocentesis at 18 weeks of gestation because of advanced maternal age, and the result showed an aberrant chromosome 4 or 46,XX,add(4) (p15.3). The woman consulted our clinics at 22 weeks of gestation and requested for repeat amniocentesis. Prenatal ultrasound revealed intrauterine growth restriction, facial cleft, vermian hypoplasia of cerebellum, micrognathia and absent stomach. Conventional cytogenetic analysis was performed on cultured amniocytes, parental bloods and cord blood. Array comparative genomic hybridization (aCGH) and quantitative fluorescent polymerase chain reaction (QF-PCR) were performed on the DNAs extracted from uncultured amniocytes and parental bloods. Fluorescence in situ hybridization (FISH) analysis was performed on cultured metaphase amniocytes.

RESULTS

aCGH analysis on uncultured amniocytes revealed arr 4p16.3p16.1 (74,447-8,732,731) × 1.0 [GRCh37 (hg19)] with an 8.66-Mb deletion of 4p16.3-p16.1 encompassing 70 [Online Mendelian Inheritance of in Man (OMIM)] genes including ZNF141, FGFRL1, TACC3, LETM1, NSD2 and NELFA. QF-PCR revealed a paternal origin of the distal 4p deletion. Conventional cytogenetic analysis revealed 46,XX,del(4) (p16.1)dn in the fetus. Metaphase FISH analysis confirmed a 4p16 deletion. The parental karyotypes were normal. The pregnancy was subsequently terminated, and a malformed fetus was delivered with typical WHS facial dysmorphism, bilateral cleft lip and palate, and preaxial polydactyly on the right hand.

CONCLUSION

aCGH, QF-PCR and FISH help to delineate the nature of a prenatally defected aberrant chromosome, and the acquired information is useful for genetic counseling.

Speech and language in Wolf-Hirschhorn syndrome: a case-study

Wolf-Hirschhorn syndrome (WHS), a condition resulting from a distal deletion of the short arm of chromosome 4, is usually associated with a severe phenotypic expression including multiple malformations, delayed psychomotor development, and profound learning disabilities. As far as communicative development is concerned, speech is usually absent and comprehension is limited to simple orders or to a specific context. There is some suggestion, however, that the developmental outcome in WHS depends on deletion size. This paper reports on an individual with WHS illustrating that a smaller deletion may result in a milder phenotype with respect to communicative abilities. This 10-year-old girl developed speech and language to a considerable degree. Although most children with this syndrome are severely limited in communicative abilities, the school-based speech-language pathologist working with a special education caseload may encounter WHS children with smaller deletions (and thus less severe phenotypes) who may profit from speech language pathology services.

LEARNING OUTCOMES

The reader will learn about the genetics, incidence, and clinical characteristics of Wolf-Hirschhorn syndrome, and about the communicative abilities and genotype/phenotype correlations in children with this syndrome.

Structural evidence of injury or malformation in the brains of children with congenital heart disease

Neurological and developmental deficits are common in children with congenital heart disease (CHD). These are due to multiple factors that include the etiology of the CHD, the effects of abnormal cardiovascular function, and the possible sequelae of open heart surgery. CHD is frequently part of a multiple malformation syndrome that includes the brain. The causes of these syndromes include known or putative genetic defects. Abnormal cardiovascular function may be associated with poor brain growth, embolic infarction, cerebrovascular thrombosis, and abscess formation. Perioperative neurological complications include diffuse hypoxic-ischemic injury (particularly in neonates who undergo more than 45 to 60 minutes of hypothermic circulatory arrest), cerebral macro- and micro-emboli, dural sinus thrombosis, and cerebral hemorrhage. Neuroimaging, especially magnetic resonance imaging, is a useful prognostic instrument, can easily display gross congenital and acquired lesions, and should be performed preoperatively in addition to genetic studies. In some instances poor brain function may not be predicted unless slow head growth or microcephaly is present and thorough preoperative neurodevelopmental evaluation is encouraged.

Prenatal diagnosis of mosaic 4p- in a fetus with trisomy 21

Mosaicism for the Wolf-Hirschhorn syndrome, del(4)(p16), is extremely rare and has not been reported in association with a numerical chromosome abnormality. We report the prenatal diagnosis of mosaic del(4)(p16) and non-mosaic trisomy 21 in a 16-week female fetus. The pregnancy ended in spontaneous abortion at 34 weeks secondary to fetal demise. The fetus had features of both 4p- and trisomy 21.

A patient with Wolf-Hirschhorn syndrome originating from translocation t(4;8) (p16.3;q24.3)pat

We present here a 7 year old girl with the clinical signs of Wolf-Hirschhorn syndrome (WHS). Only on high resolution banding was a deletion of 4p16.3 suspected in both the proband and the father. Further studies using simultaneous R banding and FISH, with cosmid probe pc847.351 containing the mildly repetitive fragment 847-EC, confirmed the diagnosis and showed a paternal balanced translocation t(4;8)(p16.3;q24.3).

FISH detection of Wolf-Hirschhorn syndrome: exclusion of D4F26 as critical site

Wolf-Hirschhorn syndrome (WHS) is due to a deletion in the terminal band of 4p16.3. Among loci that have been involved in deletions are D4S98, D4S95, D4S125, D4F26, as shown by PCR typing, Southern blot hybridization, and/or fluorescent in situ hybridization (FISH). Currently, FISH detection of WHS is predicted upon the deletion of the D4F26 locus with failure to hybridize to pC847.351, a commercially available cosmid probe. A WHS patient is shown to have an interstitial deletion, by hemizygosity at D4S98 and D4S95 but not at D4F26. This suggests that the tip of 4p, specifically D4F26, is not a critical deletion site for WHS.

Parental origin of chromosome 4p deletion in Wolf-Hirschhorn syndrome

We report on molecular studies in 7 patients with Wolf-Hirschhorn syndrome (WHC) not showing an obvious chromosome 4p deletion. Analysis of a set of polymorphic probes mapping in the 4p16.3 region showed the absence of paternal haplotypes in 5 cases, and maternal haplotypes in 2. These observations corroborate evidence for preferential paternal origin of the de novo 4p chromosome deletion. The overall results of molecular studies suggest that the preponderance of paternally derived WHC could be due, rather than to imprinting of this region, to an excess of structural rearrangements in the male meiosis, related to differences between the mechanisms of sperm and egg production.