Piebaldism in a mentally retarded girl with rare deletion of the long arm of chromosome 4

Novel retinal finding in a patient with 4q12 deletion

BACKGROUND

Chromosome 4q deletions are rare disorders phenotypically characterized by several features. The most commonly described ocular abnormalities include unilateral microphthalmia with bilateral colobomata, blue sclerae with pigmented retinal clumps, hypermetropia, and a divergent squint.

PURPOSE

To report a case of 4q12 deletion with a singular retinal feature.

MATERIALS AND METHODS

Case report.

RESULTS

A 20-year-old Caucasian female with a history of poliosis, progressive appearance of small areas of skin depigmentation along trunk and limbs since birth and diagnosis of learning deficit was referred for a complete ocular examination. The genetic counseling showed microdeletion in the 4q12 region. An audiometric test was performed, showing a progressive bilateral neurosensorial hypoacusia. Ocular examination showed the presence of multifocal, tiny, whitish deposits in the posterior pole. Multimodal imaging defined the lesions as small elevations of the retinal pigment epithelium with slight hyper-autofluorescence and staining in the late phase of fluoresceine angiography (FA). Visual acuity was 20/20. The retinal findings did not change during the three-month follow-up.

CONCLUSIONS

Although the findings herein reported have never been described before in patients affected by 4q12 mutations, we do not exclude that they could represent a manifestation of the peculiar genetic asset of the patient, related to dysfunction in pigment epithelium/neuroretinal metabolic activity.

[Leucoderma in children: Review of the literature]

BACKGROUND

Leucoderma is a frequent presenting complaint in children and it is sometimes difficult to make a definite diagnostic during the first consultation. The aim of this study is to analyse the diagnoses associated with leucoderma in children in order to propose a practical approach to their differential diagnosis.

MATERIAL AND METHODS

We performed a review of the literature using the keywords "leucoderma children review", "leucoderma Ito" and "nevus depigmentosus" in the Medline database. All relevant articles were included.

RESULTS

Four hundred and thirty-five articles were retrieved and 179 were analysed. A clinical approach was proposed in 6 articles and investigations in 15 articles.

DISCUSSION

Causal diagnosis of leucoderma may frequently be made on clinical grounds by determining the age of onset and distribution of lesions. Nevertheless, some situations require investigation. The literature is limited regarding clinical approaches and examinations in leucoderma. Herein, we present a systematic clinical and laboratory approach to the differential diagnosis of these skin disorders.

4q12-4q21.21 deletion genotype-phenotype correlation and the absence of piebaldism in presence of KIT haploinsufficiency

Chromosome 4q deletion syndrome is a rare intellectual disability disorder caused by a variety of non-recurrent deletions of 4q. We describe the evolution of the phenotypic features of a female patient with a previously unreported deletion of 4q12-4q21.21 (hg 18; 54,711,575-79,601,919). By review reported individuals with interstitial deletions extending telomeric from 4q12 have syndromic intellectual disability with variable piebaldism. We expand the phenotype to include dolichocephaly, pectus excavatum, hip dysplasia, pes planus, myopia, lens opacities, and an absence of spoken language but not of communication through sign. The proposita also did not have piebaldism suggesting again that piebaldism arises from a mechanism more complex than simple haploinsufficiency of KIT. Comparing deletions among affected individuals localizes the critical interval within 4q12-4q13.1, although the absence of molecular boundaries for nearly all reported cases precludes precise delineation and genotype-phenotype correlation.

Terminal 4q deletion syndrome

Terminal deletion of the long arm of chromosome 4, (4q) is a rare event. It is characterized by spectral phenotypic manifestations, depending upon the site and quantity of chromatin lost. The chromosomal loss which span 4 (q31-q35) segment often manifests as craniofacial anomalies, mental retardation with ocular, cardiac, genitourinary defects and pelvic/limb dysmorphism. These abnormalities are usually unilateral. We report a female child (46, XX), aged 11 months, born to nonconsanguineous parents, bearing chromosomal deletion of 4 (q31.2-35.2) segment, which has manifested as craniofacial hypoplasia of left side of face, ipsilateral ptosis, erythroderma and bilateral thumb anomalies.

De novo pericentric inversion of chromosome 4, inv(4)(p16q12) in a boy with piebaldism and mental retardation

An 8-year-old boy who was diagnosed to have piebaldism had moderate growth and mental retardation. Chromosome analysis from peripheral blood showed pericentric inversion 4(p16q12). The inversion was further confirmed by fluorescence in situ hybridization using whole chromosome painting and centromeric probes. Chromosomal analysis of parents revealed de novo inheritance of this inversion. This is the first report of pericentric inversion associated with piebald trait.

Analphoid marker chromosome in a patient with hyper-IgE syndrome, autism, and mild mental retardation

Hyper-IgE syndrome with recurrent infections (HIES) is a primary immunodeficiency disease characterized by recurrent skin and lung abscesses and extreme elevations of serum IgE, but also involving dentition, bones, and connective tissue. Although the etiology of HIES is unknown, autosomal dominant inheritance has been observed in multiple kindreds. A 17 year old male with sporadic HIES, autism, and mild mental retardation was found to have a supernumerary marker chromosome in peripheral blood lymphocytes and skin fibroblasts. Microdissection and FISH analysis of the marker chromosome showed that it was derived from a small interstitial deletion of one homologue of chromosome 4q21. Lack of hybridization of probes specific for telomeres and alphoid centromeres, including a centromere 4 specific probe, established that the marker was an analphoid ring chromosome. Comparative genotyping of transformed B-cell subclones with (M+) and without (M-) the marker chromosome showed loss of the maternal alleles in M- cells between markers D4S1569 and D4S3010. FISH using YAC clones from 4q21 confirmed the size and location of the interstitial deletion. Thus our patient's phenotypes were associated with de novo formation of a marker chromosome containing 15-20 cM of DNA deleted from his maternally derived chromosome 4. Proximal chromosome 4q therefore is a candidate region for disease genes for both HIES and autism. Identification of genes disrupted or lost during the formation of the marker chromosome as well as linkage studies in kindreds with HIES or autism may help us to understand the etiology of these complex phenotypes.

Prenatal diagnosis of de novo interstitial deletion of proximal 4q by maternal serum screening for Down syndrome

Deletion of the proximal portion of chromosome 4q is apparently rare. To our knowledge, prenatal diagnosis of the interstitial deletion of 4q12-21.1 has never been reported. We present a prenatal case of 4q deletion in association with a positive Down syndrome screening test of an elevated maternal serum free beta human chorionic gonadotrophin (beta-hCG) level. The prenatal sonogram revealed intra-uterine growth retardation (IUGR) and shortening of the femur. Facial dysmorphism included micrognathia, depressed nasal bridge and low-set ears, these anomalies were evident at the postnatal examination. All of the anomalies were consistent with those described in proximal 4q deletion syndrome. Our case suggests that chromosome studies may be indicated for patients with high maternal serum free beta-hCG and IUGR in the early second trimester.

Interstitial deletion of bands 4q12-->q13.1: case report and review of proximal 4q deletions

We report a 6 year old child with a small de novo interstitial deletion of proximal 4q, karyotype 46,XX,del(4)(pter-->q12::q13.1-->qter). She has made good developmental progress and attends normal school with minimal assistance. We review published reports and clinical findings in patients with proximal 4q deletions.

Interstitial deletion, del(4)(q12q21.1), owing to de novo unbalanced translocation in a 2 year old girl: further evidence that the piebald trait maps to proximal 4q12

A very short, microcephalic, and mentally retarded 2 year old girl showed minor anomalies including prominent occiput, delayed closure of the anterior fontanelle, high frontal hairline, prominent ears, upward slanting palpebral fissures, a small nose with bulbous tip, delayed tooth eruption and bone maturation, and short and tapering fingers and toes. She did not have a white forelock. Cytogenetic investigation disclosed a de novo unbalanced translocation between chromosomes 4 and 18 with deletion of 4q12-->q21.1. Molecular investigation showed lack of a paternal allele for the microsatellite markers D4S392 and D4S398. This case shows indirect evidence that the piebald gene maps to proximal 4q12.