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The Nude (nu) and Streaker (nustr) Mutations, Chromosome 11
Published in John P. Sundberg, Handbook of Mouse Mutations with Skin and Hair Abnormalities, 2020
The thymic agenesis found in nu/nu and nustf/nustf mice, but not the alopecia, resembles thymic agenesis of human newborns which has been called DiGeorge syndrome. Humans have hypoplasia or aplasia of the thymus with marked depletion of paracortical areas of lymph nodes. Differences in humans are that patients develop neonatal tetany and major anomalies of the great vessels. These are due to embryologic defects in the third and fourth pharyngeal pouches which cause malformation of the parathyroid and heart. Although DiGeorge syndrome does not appear to have a familial tendency,2 some familial cases have been reported to be associated with deletions in Chromosome 22.32
D-2-hydroxyglutaric (DL-2-hydroxyglutaric) aciduria
Published in William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop, Atlas of Inherited Metabolic Diseases, 2020
William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop
In the combined D-2 and L-2 hydroxyglutaric patients in whom the fundamental defect is in SLC25A1, the gene for the citrate carrier CIC. Deficiency impairs the efflux of citrate and isocitrate from mitochondria in exchange for malate. This leads to depletion of cytosolic citrate and accumulation of mitochondrial citrate. The gene is on chromosome 22q11 in the area deleted in DiGeorge syndrome. A variety of mutations was found in 12 patients, eight of whom were homozygous [12]. Missense mutations such as c.844C>T were the most common; there was one nonsense mutation, two frameshifts and a mutation which caused a splicing error. In two patients, no protein was detected on immunoblot.
Microarrays
Published in Moshe Hod, Vincenzo Berghella, Mary E. D'Alton, Gian Carlo Di Renzo, Eduard Gratacós, Vassilios Fanos, New Technologies and Perinatal Medicine, 2019
Melissa Stosic, Jessica L. Giordano, Brynn Levy, Ronald Wapner
Posttest genetic counseling should utilize the published literature and laboratory report to further delineate the risks associated with a positive CMA, including any recommended follow-up testing such as fetal echocardiogram or evaluation of other relatives. In the case of an abnormal CMA, referrals to pediatric genetics and/or genetic counselors and support groups specific to that condition should be provided. Discussion of pregnancy options as well as follow-up phone calls with these patients is appropriate. In most cases, interpretation of the CMA results is straightforward as a CNV associated with a well-known syndrome or associated with a specific disorder is identified. However, in some cases, interpretation can be more complicated and requires significant counseling skill. As with all genetic disorders, CNV results can be associated with variable expressivity in which some individuals with the finding may be mildly affected, whereas others have a much more severe phenotype. In these cases, prognostic prenatal prediction is not possible. DiGeorge syndrome caused by a 22q11.2 deletion is an example in which normal-appearing parents can have a fetus with significant anomalies. Similarly, there can be significant cognitive impairment and psychiatric disorders in some but not all individuals with the same deletion. In these cases, referral for genetic counseling is recommended.
Current updates and future perspectives in the evaluation of azoospermia: A systematic review
Published in Arab Journal of Urology, 2021
Nahid Punjani, Caroline Kang, Dolores J. Lamb, Peter N. Schlegel
CRKL encodes the SRC homology 2 (SH2) and SH3 homology adaptor protein that plays a role in mediating tyrosine kinase signalling pathways [54]. This well-known gene causes many of the major anomalies present in 22q11.2 deletion syndrome (DiGeorge syndrome) and was more recently defined as the gene-dosage defect that causes the genitourinary abnormalities found in both DiGeorge syndrome and seemingly non-syndromic patients with upper and lower tract genitourinary anomalies. Associated birth defects included micropenis and cryptorchidism, but the histopathology identified in the cryptorchid mouse model was atypical spermatogenic failure unlike the spermatogenic arrest present in individuals (or mice) with cryptorchid testis [54]. This protein therefore has a unique role in testicular descent, spermatogenesis, and like MAZ described above is associated with numerous other systemic conditions such as cardiac, developmental, gastrointestinal, ocular, auditory, and craniofacial abnormalities [3].
Variability in Neuropsychological Phenotypes in Patients with 22Q11.2 Deletion Syndrome: Case Series
Published in Developmental Neuropsychology, 2021
Andrea Wierzchowski, Savanna Sablich-Duley, Veronica Bordes Edgar
Medical and Developmental History. Emma (pseudonym) was a 5-year-old White/Hispanic/Latina female. Gestation and pregnancy were uncomplicated. She was diagnosed, within the first year of her life, with DiGeorge Syndrome characterized by Tetralogy of Fallot with an absent pulmonary valve status post repair with ventral septal patch closure. Emma had undergone multiple hospitalizations and surgeries secondary to heart defects, pharyngeal flap and full mouth dental rehab, placement of ear tubes, tonsillectomy, and adenoidectomy. Emma wore hearing aids secondary to conductive hearing loss (mild on right and mild to moderate loss on left) and her vision was corrected with glasses.
Atypical presentation of Cat Eye Syndrome in an infant with Peters anomaly and microphthalmia with cyst
Published in Ophthalmic Genetics, 2020
Benjamin Katz, Jennifer Enright, Steven Couch, George Harocopos, Andrew R. Lee
Our patient’s supernumerary region of chromosome 22 at q11.1 to q11.21 included the DiGeorge syndrome critical region. Peters anomaly and other anterior segment dysgeneses have been described in association with DiGeorge syndrome, also known as 22q11.2 deletion syndrome and velocardiofacial syndrome (19–22). However, to our knowledge, there have been no reports in the literature of Peters anomaly in the setting of CES (i.e. supernumerary 22q11.2). Although corneal opacities were noted in some case reports of CES, none of these reports noted the other associated anterior segment findings of Peters anomaly, making this a unique ocular presentation of this syndrome (23,24).