Cryptic 7q36.2q36.3 deletion causes multiple congenital eye anomalies and craniofacial dysmorphism

Prenatal detection of chromosome 7q deletion with duplication: A case report and literature review

RATIONALE

With advances in prenatal diagnostic techniques, chromosomal microdeletions and microduplications have become the focus of prenatal diagnosis. 7q partial monosomy or trisomy due to a deletion or duplication of the 7q end is relatively rare and usually originates from parents carrying a balanced translocation.

PATIENT CONCERNS

Noninvasive prenatal screening (NIPT) showed a fetus with partial deletion and duplication of chromosome 7q. It was not possible to determine whether the fetus was normal.

DIAGNOSES

Conventional chromosome G-banding and chromosome microarray analysis (CMA) were performed on fetal amniotic fluid samples and parental peripheral blood samples.

INTERVENTIONS

The pregnant women were given detailed genetic counseling by clinicians.

OUTCOMES

The fetal karyotype was 46, XY on conventional G-banding analysis. The CMA test results showed a deletion of approximately 7.8 Mb in the 7q36.1q36.3 region and a duplication of 6.6Mb in the 7q35q36.1 region. The parents' karyotype analysis and CMA results were normal, indicating a new mutation.

LESSONS

CMA molecular diagnostic analysis can effectively detect chromosomal microdeletions or microduplications, clarify the relationship between fetal genotype and clinical phenotype, and provide a reference for prenatal diagnosis of chromosomal microdeletion-duplication syndrome.

Two Cases of Ocular Manifestations in Patients with Microdeletion of the Chromosome 7 Long Arm

Purpose: We report ocular manifestations in two patients with 7q microdeletion. Case summary: (Case 1) A 62-day-old male infant was admitted to the ophthalmology outpatient department for ocular examination after being diagnosed with microdeletion of chromosome seven (7q36.2q36.3 deletion) in DNA microarray comparative genomic hybridization (DNA microarray CGH) and fluorescence in situ hybridization (FISH) tests. Fundus examination showed optic disc hypoplasia in both eyes and retinopathy of prematurity, accompanied by retinal hemorrhage in his right eye. Around the age of 24 months, the patient was diagnosed with intermittent exotropia with anisometropia and was prescribed spectacles. (Case 2) A 3-year-old male infant was referred to the ophthalmology clinic to evaluate poor fixation, which was found during rehabilitation therapy for cerebral palsy and developmental delay. Fundus examination showed an increased cup/disc ratio bilaterally. A flash visual evoked potential test indicated a decrease in amplitude in his right eye. Intermittent exotropia of forty prism diopters was observed. DNA microarray CGH and FISH tests performed at another hospital revealed microdeletion of chromosome seven (7q35 microdeletion) and CNTNAP2 gene loss. Conclusions: When genetic anomalies associated with ocular development are identified, it is necessary to detect the ophthalmic abnormalities early and provide the appropriate treatment to allow for the development of normal visual function.

Prenatal ultrasound-assisted identification of multiple malformations caused by a deletion in the long-arm end of chromosome 7 and review of the literature

Clinical cases of chromosome 7 long-arm end deletion are rare. Generally, 7q terminal deletion syndrome results in complex clinical phenotypes, such as microcephaly, growth and development retardation, holoprosencephaly, and sacral hypoplasia. Herein, we report the genetic and clinical features of a fetus with multiple malformations observed by prenatal ultrasound. The results showed that there was a large fragment deletion of approximately 27.7 Mb in 7q32.3-qter. The induced fetus showed facial abnormalities of cleft lip and palate, and some organ structural abnormalities (such as diaphragmatic hernia and polycystic renal dysplasia) were observed by autopsy and pathology. To provide more reliable information for disease diagnosis and genetic counseling, we reviewed and analyzed the reported cases of isolated 7q terminal syndrome.

Kaposi sarcoma, oral malformations, mitral dysplasia, and scoliosis associated with 7q34-q36.3 heterozygous terminal deletion

Chromosome 7 germline macrodeletions have been implicated in human congenital malformations and developmental delays. We herein report a novel heterozygous macrodeletion of 7q34-q36.3 in a 16-year-old girl originally from West Indies. Similar to previously reported cases of germline chromosome 7q terminal deletions, our patient has dental malposition, and developmental (growth and intellectual) delay. Novel phenotypic features include endemic Kaposi sarcoma (KS), furrowed tongue, thoracolumbar scoliosis, and mild mitral valve dysplasia. The occurrence of human herpes virus 8-driven KS, in a child otherwise normally resistant to other infectious agents and without any other tumoral lesion, points to a very selective immunodeficiency. While defects in organogenesis have been described with such macrodeletions, this is the first report of immunodeficiency and cancer predisposition.

Three new cases of terminal deletion of the long arm of chromosome 7 and literature review to correlate genotype and phenotype manifestations

Partial monosomy of the long arm of chromosome 7 has been characterized by wide phenotypic manifestations, but holoprosencephaly (HPE) and sacral agenesis have frequently been associated with this chromosomal deletion. A clear relationship between genotype and phenotype remains to be defined in the 7q deletion syndrome. Three patients (1, 2, and 3) were investigated with 7q terminal deletion and compared with similar deletion cases in the literature in order to stratify the phenotypes associated with 7q35 and 7q36 terminal deletion patients. Patients 1, 2, and 3 were carrying a de novo terminal deletion at bands 7q36.2, 7q35, and 7q36.1, respectively. In patient 3, a small Xq28 duplication was also identified by array-CGH. Our patients presented with heterogeneous phenotypic manifestations, which could imply the possible role of environmental factors (multifactorial inheritance), structural variations in the non-coding regions, penetrance, and/or polymorphism. The varying length of deletion was also taken into account. Growth retardation was the most frequent symptom found in both 7q35 and 7q36 patients we reviewed. The occurrence of HPE and sacral malformation together was seen in less than 10% of the reviewed cases in both kinds of deletion. HPE was associated mainly in cases with an unbalanced translocation.

Dental developmental abnormalities in a patient with subtelomeric 7q36 deletion syndrome may confirm a novel role for the SHH gene

Studies in mice demonstrated that the Shh gene is crucial for normal development of both incisors and molars, causing a severe retardation in tooth growth, which leads to abnormal placement of the tooth in the jaw and disrupted tooth morphogenesis. In humans the SHH gene is located on chromosome 7q36. Defects in its protein or signaling pathway may cause holoprosencephaly spectrum, a disorder in which the developing forebrain fails to correctly separate into right and left hemispheres and that can be manifested in microforms such as single maxillary central incisor. A novel role for this gene in the developing human primary dentition was recently demonstrated. We report a 12-year old boy with a de novo 7q36.1-qter deletion characterized by high-resolution karyotyping, oligonucleotide aCGH and FISH. His phenotype includes intellectual disability, non-verbal communication, hypospadia, partial sacral agenesis and absence of coccyx, which are distinctive features of the syndrome and mainly correlated with the MNX1, HTR5A and EN2 genes. No microforms of holoprosencephaly spectrum were observed; but the patient had diastema and dental developmental abnormalities, such as conical, asymmetric and tapered inferior central incisors. The dental anomalies are reported herein for the first time in subtelomeric 7q36 deletion syndrome and may confirm clinically a novel role for the SHH gene in dental development.

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We report a boy with 7q-, dental developmental abnormalities and sacral agenesis.

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We propose novel roles for SHH gene related to dental developmental abnormalities.

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The MNX1 gene may be associated with caudal deficiency sequence in 7q- patients.

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HTR5A and EN2 may be related to abnormal brain development in 7q- patients.