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Basic genetics and patterns of inheritance
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Another type of structural abnormality is a deletion, in the absence of a translocation. Deletions can be terminal, that is, at either end of the chromosome, or interstitial, within the short or long arm of the chromosome. As can be imagined, there is an almost infinite number of possible deletions that can occur as a result of accidents during meiosis. However, some specific deletions are seen more frequently. One such relatively common terminal deletion is 5p- or cri du chat syndrome. Cri du chat syndrome is associated with microcephaly and mental retardation in all cases, congenital heart defects in about 30%, and craniofacial dysmorphic features, including a round face, epicanthal folds, hypertelorism, and dysplastic ears (19). Newborns with cri du chat syndrome have a mewing or cat-like cry, for which the syndrome was named. Another fairly frequent terminal deletion is 4p- or Wolf–Hirschhorn syndrome, a disorder associated with mental retardation, growth deficiency, and distinctive craniofacial dysmorphic features. Patients with Wolf–Hirschhorn have microcephaly, a prominent glabellar region, hypertelorism, strabismus, cleft lip and/or palate, and micrognathia (19). They may have associated cardiac, renal, and genital anomalies. These types of deletions are usually visible on routine karyotype analysis due to their large size. However, deletions can obviously vary widely in size; some are too small to be seen on routine studies and will require FISH analysis or chromosome microarray analysis to be detected.
Microdeletion Syndromes
Published in Merlin G. Butler, F. John Meaney, Genetics of Developmental Disabilities, 2019
Gopalrao V. N. Velagaleti, Nancy J. Carpenter
Cri du chat syndrome is caused by a deletion of the short arm of chromosome 5 (del 5p). The majority of cases are due to terminal deletions or interstitial deletions, but unbalanced translocations with partial loss (monosomy) of 5p and partial gain (trisomy) of another chromosome may also occur. The deletions are usually de novo, although a few familial cases have been described. Unbalanced translocations result from segregation of a balanced translocation in one of the parents and passed to the child. Mosaicism for the deletion has been reported in several affected patients and in one unaffected parent (28).
Congenital alacrima
Published in Orbit, 2022
Zhenyang Zhao, Richard C. Allen
Alacrima is inconsistently described in some congenital disorders as an atypical feature. Two cases of alacrima are reported in association with blepharophimosis-ptosis-epicanthus inversus syndrome (BPES), which is an autosomal dominant condition caused by mutation in FOXL253,54 Interestingly, one of the patients has bilateral lacrimal gland agenesis54 while the other has intact lacrimal glands.53 Decreased tear secretion is confirmed in 6 out of 7 patients from Howard’s series of the cri-du-chat syndrome.56 A recent publication on Cohen syndrome revealed a patient with prepubertal alacrima confined to emotional tear production with intact basal tear secretion.57 Patients with alacrima are also found in Opitz Frias syndrome and Pierre Robin sequence.55,58
The validity of a measure of adjustment in siblings of children with developmental and physical disabilities: a brief report
Published in Developmental Neurorehabilitation, 2021
Stian Orm, Torun Vatne, Yngvild B. Haukeland, Wendy K. Silverman, Krister Fjermestad
In a commendable effort to include user-perspectives, the SPQ was designed initially for siblings of children with cancer and items were selected based on discussion with siblings and oncology specialists.7 Based on a sample of 90 siblings of children with cancer, an exploratory factor analysis identified that 23 items loaded onto four factors with internal consistency α ≥ .65. The factors were intrapersonal adjustment (e.g., thoughts and feelings about cancer); interpersonal adjustment (e.g., chores and care tasks); communication (e.g., openness); and fear.7 Convergent validity was not established. In a cross-sectional study of 44 siblings of children with Cri du chat-syndrome,9 the authors used the SPQ. The authors did not report internal consistency or factor structure, however, so the SPQ’s psychometric properties when used with siblings of children with disabilities other than cancer remained unknown.
Prenatal Diagnosis of 5p Deletion Syndrome with Brain Abnormalities by Ultrasonography and Fetal Magnetic Resonance Imaging: A Case Report
Published in Fetal and Pediatric Pathology, 2020
Didem Kaymak, Verda Alpay, Hakan Erenel, İbrahim Adaletli, Nil Comunoglu, Riza Madazli
Cri du chat syndrome or 5p deletion syndrome, first described by Lejeune and collaborators in 1963, is a clinically recognizable and one of the most common contiguous gene deletion disorder, with an estimated frequency of 1:15,000 to 1:50,000 live births [1]. This syndrome results from a deletion of the short arm of chromosome 5, ranging from the entire short arm to the critical region of 5p15.2 [1]. Clinical features of cri du chat syndrome include, a high-pitched catlike cry, craniofacial dysmorphic features such as round face, micrognathia, hypertelorism, epicanthal folds, low-set ears, abnormal dermatoglyphics, microcephaly and severe psychomotor and developmental delay [2]. The deletion of multiple genes on the distal part of the short arm of chromosome 5 is assumed to be responsible for the phenotype. Although the features of 5p deletion syndrome are well known postnatally, prenatal findings are generally related to abnormal ultrasound findings and few cases have been reported in the literature [3]. We present sonographic features and magnetic resonance imaging (MRI) findings of pontocerebellar hypoplasia, vermis hypoplasia, mild ventriculomegaly, and cortical hypoplasia in a case of prenatally diagnosed 5p deletion syndrome.