New insights into the phenotypes of 6q deletions

Abstract

Deletions of chromosome 6q are rare. We report 3 new patients with 6q deletions. Case 1 is a male with an interstitial deletion [del(6)(q13q14.2)], hypotonia, speech delays, and minor anomalies. Case 2 is a male with an interstitial deletion [del(6)(q16.2q22.32)] and malformations, including truncus arteriosus and bilateral oligodactyly. Case 3 is a male with a terminal deletion [del(6)(q25.2)] with retinal pits, hydrocephalus, atrioventricular canal, and hydronephrosis. The findings in our patients and those from 57 previously reported cases demonstrated 3 phenotypic groups associated with 6q deletions. Group A [del(6)(q11-q16)] had a high incidence of hernias, upslanting palpebral fissures, and thin lips with lower frequency of microcephaly, micrognathia, and heart malformations. Group B [del(6)(q15-q25)] was associated with increased intrauterine growth retardation, abnormal respiration, hypertelorism, and upper limb malformations. Group C [del(6)(q25-qter)] was associated with retinal abnormalities, cleft palate, and genital hypoplasia. The only universal finding among all patients with 6q deletions was mental retardation. Other findings common to all 3 groups included ear anomalies (90%), hypotonia (82%), and postnatal growth retardation (68%).

Clinical, genetic, and molecular aspects of split‐hand/foot malformation: An update

“…An SHFM locus on chromosome 6q has been suggested in patients with SHFM and other limb anomalies associated with rearrangements in this region, including deletions and a translocation [Braverman et al, 1993;Viljoen and Smart, 1993;Gurrieri et al, 1995;Pandya et al, 1995;Correa-Cerro et al, 1996;Hopkin et al, 1997;Tsukahara et al, 1997;Duran-Gonzalez et al, 2007]. Disruption of the gene SNX3 at 6q21 by a balanced translocation was identified in a patient with microcephaly, microphthalmia, ectrodactyly, prognathism syndrome (MMEP; OMIM 601349), a rare syndromal form of SHFM [Viljoen and Smart, 1993;Vervoort et al, 2002].…”

Interstitial deletion of 6q25.2–q25.3: a novel microdeletion syndrome associated with microcephaly, developmental delay, dysmorphic features and hearing loss

“…2,17 (Table 1). In the case of Hopkin et al, 2 the proband had macrocephaly because of hydrocephalus, whereas in Valtat et al, 17 the FOC was 1.5 SD below the mean.…”

“…Hearing loss has been reported only in a minority of publications. 1,2,6,8,9 Most of the reported deletions were identified and characterized based on routine karyotyping with no further attempt to delineate the breakpoints. We determined the size, extent and genomic content of four cases involving interstitial deletion of 6q25.…”

A de novo Proximal 6q Deletion Confirmed by Array Comparative Genomic Hybridization

“…Clinical manifestations of 6q deletions vary according to the size and location of the deleted regions. Using conventional cytogenetic methods, Hopkin et al [2] proposed three phenotypic groups associated with 6q deletions, namely, proximal The patient described in the present study is the second case of proximal deletion of 6q diagnosed in the Korean population. The patient was referred for multiple anomalies, including cleft lip, flat face, low-set ears, and hip dislocation.…”

“…To date, only one case with a deletion of the long arm of chromosome 6 has been identified through standard cytogenetic analyses in Korean patients [1]. The clinical features of 6q deletions, including facial dysmorphism, mental retardation, developmental delay, and defects of the brain, heart, lungs, bones, and joints, vary with the size and location of the deleted regions [2]. Here, we report a case of interstitial 6q deletion associated with facial and skeletal anomalies, umbilical hernia, and brain defects in a female infant.…”