Clinical and epilepsy characteristics in Wolf-Hirschhorn syndrome (4p-): A review

Wolf-Hirschhorn syndrome (WHS) is araredisorderwithan estimated prevalence being around 1 in 50,000 births. The syndrome is caused by the deletion of a critical region (Wolf-Hirschhorn Syndrome Critical region- WHSCR) on chromosome 4p16.3. WHS is clinically characterized by pre-and postnatal growth restriction, hypotonia, intellectual disability, craniofacial dysmorphismand congenital fusion anomalies. The clinical aspects are variable due to the deletion size.Consistently, epilepsy is one of the major concerns for parents and professionals caring for children with WHS. Seizures tend to occur in over 90% of patients, with onset within the first 3 years of life, and a peak incidence at around 6-12 months of age. Approximately 20% of patients had the first seizure onset within the first 6 months of age, almost 50% at 6 to 12 months of age and about 25% later than 12 months of age. The main types of epileptic seizures occurring in patients with WHS were generalized tonic-clonic seizures (around 70%). These were followed by tonic spasms (20%); focal seizures with impaired awareness (12%) and clonicseizures in 7% of patients.Seizures are often triggered by fever, followed by infections of various systems. Particularly, half of WHS patients experience status epilepticus in the first years of life, which can be fatal. Due to limited number of reports on the topic of EEG abnormalities in epilepsy among WHS patients, it is difficult to determine whether there are any characteristic deviations for WHS. Although more than 300 persons with WHS have been reported in the literature, there is sparse knowledge about epilepsy and methods of its anti-seizure medication (ASM) management with an assessment of their effectiveness. The purpose of this systematic review is to briefly summarize achievements and advances in the field of epilepsy in Wolf-Hirschhorn syndrome.

The delineation of the Wolf-Hirschhorn syndrome over six decades: Illustration of the ongoing advances in phenotype analysis and cytogenomic technology

Since Hirschhorn's description in 1961, the history and chronology of the clinical, cytogenetic, and molecular characterization of Wolf-Hirschhorn syndrome (WHS) elegantly demonstrates the remarkable advances in genetic technology over the last six decades that have paralleled the delineation of the phenotype. After mention in the Human Chromosome Newsletter of a child with a visible deletion of the top of a B chromosome group, 4-5, Hirschhorn and colleagues companioned their report with that of Wolf et al. in Humangenetik in 1965, and the condition was recognized and named. The 1960-1970s witnessed the description of many of the now classic chromosome disorders, including WHS, while HRB allowed for the recognition of chromosome syndromes with smaller deletions/duplications. FISH probes, developed in the next two decades, enabled the characterization of the critical region of WHS and improved clinical diagnosis with subtelomeric probes. Cytogenomic microarray in the early-mid 2000s led to both improved diagnosis of WHS patients and documentation of microdeletions of <5 megabases, helping to characterize the critical regions for specific component phenotypes (e.g., seizures, face). Recently exome sequencing technology has led to the discovery of WHS patients with WHSC1 loss of function variants, displaying some cardinal features of the phenotype (face, growth, and developmental delay).

Natural history study of adults with Wolf-Hirschhorn syndrome 1: Case series of personally observed 35 individuals

Wolf-Hirschhorn syndrome (WHS) is a contiguous gene disorder, clinically delineated by prenatal and postnatal growth deficiency, distinctive craniofacial features, intellectual disability, and seizures. The disorder is caused by partial loss of material from the distal portion of the short arm of chromosome 4 (4p16.3). Although more than 300 persons with WHS have been reported in the literature, there is sparse, if any, long-term follow-up of these individuals and thus little knowledge about course and potential further complications and health risks during adulthood and advanced age. This study attempted to assess medical conditions and function of adult individuals with WHS. It was one component of a two-part investigation on adults with WHS. The other part of the study is the patient-reported outcomes study reported elsewhere. About 35 individuals with WHS (26 females; nine males), aged between 19 and 55 years were recruited. About 25 individuals were personally observed at the IRCCS Stella Maris Foundation by A.B. and followed up between 5 and 20 years; and 10 were recruited from the 4p-Support Group, The United States. Of note, 23/35 (66%) are close to total care. About 11 out of 35 (31%) were partly self-independent, requiring supervision on certain daily routines, and 1 out of 35 (3%) was fully independent. However, a positive perspective is given by the overall good health enjoyed by the 66% of our cohort of individuals. Overall, quality of life and level of function into adulthood appear to be less critical than anticipated from previous studies.

Natural histories of patients with Wolf-Hirschhorn syndrome derived from variable chromosomal abnormalities

Wolf-Hirschhorn syndrome (WHS) is a subtelomeric deletion syndrome affecting the short arm of chromosome 4. The main clinical features are a typical craniofacial appearance, growth deficiency, developmental delays, and seizures. Previous genotype-phenotype correlation analyses showed some candidate regions for each clinical finding. The WHS critical region has been narrowed into the region 2 Mb from the telomere, which includes LETM1 and WHSC1; however, this region is insufficient to cause "typical WHS facial appearance". In this study, we identified 10 patients with a deletion involving 4p16.3. Five patients showed pure terminal deletions and three showed unbalanced translocations. The remaining patients showed an interstitial deletion and a suspected inverted-duplication-deletion. Among 10 patients, one patient did not show "typical WHS facial appearance" although his interstitial deletion included LETM1 and WHSC1. On the other hand, another patient exhibited "typical WHS facial appearance" although her small deletion did not include LETM1 and WHSC1. Instead, FGFRL1 was considered as the candidate for this finding. The largest deletion of 34.7 Mb was identified in a patient with the most severe phenotype of WHS.