Discussion
2q37 deletion syndrome first appeared in the literature in 1989. Since then, approximately 74 children and adults have been presented in the medical literature with 2q37 gene deletion with no additional chromosomal involvement [8]. In 2004, US geneticist Dr. Kari Casas described 66 cases in addition to describing 6 case reports [8].
2q37 deletion syndrome is a rare disease that has affected around 100 reported cases worldwide [9]. The deletion results in developmental delay, brachydactyly of the third to fifth digits and/or toes, obesity, short stature, change of facial appearance, and an autism spectrum disorder [3]. Patients with deletion syndrome also have some form of mental retardation [10].
We report an American female patient with a 2q37.3 deletion that was confirmed by comparative genomic hybridization (CGH) plus single nucleotide polymorphism (SNP). Although clinical presentation is variable, almost all patients have some degree of mental retardation and facial dysmorphism. The patient presented with easy fatigability, gross motor delay, and low muscle tone. An echo was performed, which revealed a patent foramen ovale with a left-to-right shunt. A cardiovascular exam found that the heart experienced strong peripheral pulses with a brisk capillary refill. The patient is otherwise healthy with no dysmorphic features. The HEENT exam revealed a clear oropharynx with moist mucous membranes.
Congenital heart defects have been found in around 20% of patients with 2q37 deletion syndrome. Both septal defects and aortic coarctation have been described in patients with 2q37 deletion syndrome [3]. The patient presented does not have aortic coarctation but does suffer from the presence of a patent foramen ovale in the atrial septum, which was confirmed using an echo. The ascending aorta, transverse arch, and descending aorta were also found to be wide open and not blocking blood flow.
The patient is growing and developing normally, both physically and mentally. Growth hormone deficiency has been found in 4 patients with 2q37 gene mutations, which led to short stature. All 4 patients experienced improved growth following growth hormone administration [11-13].
The better status of the patient who presented with no mental or physical developmental abnormalities or delays can be attributed to the size of the deletion. The patient had a gene deletion size of 2.63 MB. The largest deletion is 10 MB; most are usually greater than 3 MB [14]. Almost 30% of patients with 2q37 deletion syndrome have major malformations. These generally include the gastrointestinal, nervous system, and cardiac abnormalities [3].