A rare case report of Jacob syndrome (47, XYY) with ambiguous genitalia and intellectual disability

Abstract

Jacob syndrome, also known as XYY syndrome, is a genetic anomaly distinguished by the presence of an additional Y chromosome, resulting in a rare variation in sex chromosomes. Jacob syndrome is a rare chromosomal aneuploidy that occurs in approximately 1 out of every 1000 male newborns. Determining the diagnosis of Jacob syndrome presents challenges. The patient in this case exhibited genitalia of uncertain or indeterminate sex characteristics with several comorbidities, including microcephaly, hypotonia, impaired suction reflex, constipation, respiratory distress syndrome, stunted growth, wide fontanelles, and umbilical hernia. In addition, the genitalia showed ambiguous characteristic, penile chordee, and hypospadias. Both testicles are palpable but are located in the ileum region (undescensus testes). After confirming the presence of testicles through physical examination, the patient underwent a karyotype analysis, which revealed a chromosomal composition of 47, XYY with a mosaic pattern. The patient also had a thyroid function examination in stable condition, indicating central hypothyroidism. Orchidopexy, chordectomy, and urethroplasty operations have been performed to correct genital abnormalities. Speech delays and developmental disorders in patients are also the main problems in Jacob syndrome patients. Cognitive Adaptive Test (CAT)/ Clinical Linguistic & Auditory Milestone Scale (CLAMS) (Caput scale) examination revealed that the patient had intellectual dysfunction. The approach to both parents has been carried out by approaching risk factors, current clinical conditions, and the patient's prognosis in subsequent developments.