Molecular cytogenetic characterization of a de novo mosaic supernumerary ring chromosome 7: Report of a new patient

Abstract

Here, we report on a patient with a de novo, mosaic, supernumerary r(7) chromosome.The patient (Fig. 1a,b), a 10-year-old girl, was born at 41 weeks of gestation after an uneventful pregnancy. She was the first child of healthy and unrelated parents, age 30 (mother) and 31 (father); her younger brother (5-year-old) was healthy. Family history was negative for congenital anomalies and/or psychomotor retardation excluding a father's cousin with language developmental delay; unfortunately, he was not available for karyotype or clinical investigation.The birth weight was 4,030 g (>97th centile), length 51 cm (75th centile) and OCF 36 cm (50th centile). No clinical symptoms were reported in the neonatal period. Her motor development was slightly delayed: she was hypotonic at birth and was sitting at age of 9 months; walking abilities were in the normal range and since the age of 12 months, she could walk without support. However, speech was severely delayed: first words were not until 3 years of age, and her language skills were delayed with poor performances on the expressive side. No hearing loss was detected.She was referred by the local pediatrician at age of 5 years because of language delay. At this time her weight was 24.8 kg (95th centile), height 114 cm (90th centile), and OCF 53 cm (97th centile). Physical examination showed a flat face, high and prominent forehead, deep-set eyes, short nose, prominent nasal root close to frontal bone, short philtrum, thick columella, thin lips, relative microstomia with downturned corners, and low set ears. Palmar creases and digits were normal but her fingers had wide nails; a partial cutaneous syndactyly was present between 2nd and 3rd toe. No signs of premature puberty were present, but she showed hirsutism on the dorsal side of her limbs and a café-au-lait macula on the abdomen. Ophthalmology evaluation showed a mild astigmatism. A soft cardiac murmur was present, but cardiac evaluation, EKG, and heart echocardiography were normal. Abdominal ultrasound revealed no visceral anomalies. A cerebral MRI showed dilatation of the ventricles and cisterna magna, whereas the results of an awake EEG were in the normal range. Hematologic and neuro-metabolic screenings were normal.Her slightly retarded psychomotor development improved with time. Recently, she demonstrated no learning difficulties at school and her cognitive development fell into normal lower limits (WISCR scale). Her performances were lowered by verbal difficulties (mostly in the phonologic, semantic and syntactic areas).Karyotype analysis of 100 metaphases showed the presence of a supernumerary marker chromosome (SMC) in about 50% of cells. The marker was shaped like a ring, C-band positive, DA-DAPI and AgNOR negative. Parental karyotypes were normal.

A unique case of female pseudohermaphroditism with 21-hydroxylase deficiency and small supernumerary marker chromosome 7

“…As was observed in our patient, facial anomalies are non-specific, but some traits are common to both ring chromosome 7 [r(7)] carriers and patients with WBS duplication, and thus they can be associated with 7q proximal region triplication. Our patient shares a prominent forehead, a triangular face, a high nasal bridge, normal eyes, thin lips, short philtrum and normal ears (21) with the other patients. By contrast, other aspects, such as hirsutism, were observed in our case and other cases as well (21).…”

“…Our patient shares a prominent forehead, a triangular face, a high nasal bridge, normal eyes, thin lips, short philtrum and normal ears (21) with the other patients. By contrast, other aspects, such as hirsutism, were observed in our case and other cases as well (21). These features should be carefully sought when a new case of r(7) is discovered, since they could represent helpful clues to better delineate the r(7) phenotype.…”

Molecular cytogenetic analysis and clinical manifestations of a case with de novo mosaic ring chromosome 7

“…Monosomy 7, one complete ring, supernumerary large rings, and duplicated rings of chromosome 7, were detected. Most previous reported cases of supernumerary ring chromosome 7 showed a majority of cells with a normal karyotype, in addition to some cells with a partial trisomy containing small rings [20-26]. Here we present a newborn girl that survived with a mosaic karyotype with a complete supernumerary ring chromosome 7 and a few monosomy 7 cells, without any cell with normal karyotype detected in peripheral lymphocytes.…”

Bilateral Cleft Lip and Palate in Ring Chromosome 7 Syndrome: A Case Report and Review of Clinical Characteristics

“…In some of these cases, patients could also present with severe intellectual disability, speech delay, and other atypical features. [29][30][31] Ring chromosome 7 as a part of complex karyotypes usually correlate with malignancies, typically myelodysplastic syndrome, leukaemia, and lymphoma. 11,24,26,32,33 Ring chromosome 7 accompanied with trisomy of chromosome 8 has been reported to manifest as pediatric hepatosplenic T-cell lymphoma.…”