It you lift the arm up, it literally drops. Sensation is usually intact. There might be slightly decreased sensation in the other arm, but these are younger kids, so theyre not always so cooperative in giving you a good sensory exam. Childrens Mercy Hospital, which had three or four cases in 2014, reported that the MRI images and symptoms closely mimicked polio. They reported: "The sudden onset of flaccid paralysis in single or multiple limbs with absolutely no sensory findings, the MRIs all showing uniformly a signal increase in the ventral horns of the spinal cord — this is exactly the same region of the spinal cord affected in polio ... Almost all of the patients have an increase in their white blood cells in the cerebrospinal fluid. Some of the patients have brainstem findings and cranial-nerve findings. "Of 64 patients meeting the CDC criteria before October 29, 2014, 80% had had a preceding respiratory illness and 75% reported fever in the days leading up to limb weakness, the onset of which was generally abrupt. By November 20, the number of confirmed cases stood at 88 from 29 states.The CDC requested that physicians provide information about cases meeting these criteria: patients diagnosed after August 1, 2014, who are no older than 21 years of age, showing acute onset of focal limb weakness, with a spinal-cord lesion largely restricted to grey matter visualized by MRI.In November 2018, the CDC reported that they were investigating 286 cases, with at least 116 confirmed cases in 31 states.
Skin may be dry and coarse, excessively wrinkled around the face and loose around the hands yet tight around the finger joints, leading to diminished use of the fingers.Genital defects may include: ambiguous genitalia, a displaced and/or atypically small penis (micropenis), an absent scrotum around the testes and undescended testicles. Finally, alopecia and thin, sparse hair are also frequently observed. Causes
Like Barber–Say syndrome, AMS is caused by mutations in the TWIST2 gene that affect a highly conserved residue of TWIST2 (twist-related protein 2). TWIST2 is a basic helix-loop-helix transcription factor that binds to E-box DNA motifs (5-CANNTG-3) as a heterodimer and inhibits transcriptional activation. Because TWIST2 mediates mesenchymal stem cell differentiation and prevents premature or ectopic osteoblast differentiation, mutations in TWIST2 that disrupt these functions by altering DNA-binding activity could explain many of the phenotypes of AMS. Current research points to the substitution of the wild-type amino acid for Lysine at TWIST2 residue 75 as a significant genetic cause of AMS.AMS is inherited in an autosomal dominant manner, in which an affected individual needs only one copy of the mutant allele in order to express the disease. Mechanism
The mesenchyme is a mesodermal embryonic tissue that can develop into a multitude of different tissues depending on the needs of the developing embryo. The mesenchyme can develop into blood, cartilage, and membranes. In a normal patient, TWIST2 is highly expressed during embryonic development, specifically in the craniofacial development and chondrogenisis.