Neonates with arthrogryposis multiplex congenita may have facial dysmorphysm. Facial dysmorphysm and arthrogryposis multiplex congenita occur in many disorders including trisomy 13 and 18 syndromes, Pena-Shokeir I and II syndromes, Antley-Bixer syndrome, Sheldon-Fremann syndrome, Beals syndrome, Smith-Lemli-Opitz syndrome, and Zellweger syndrome.
Arthrogryposis may be due to neurological or nonneurological causes. Neurological arthrogryposis multiplex congenita may be due to central or peripheral abnormalities. Nonneurological arthrogryposis multiplex congenita may be due to cartilaginous abnormalities or physical constraint from movement.

Cartilaginous abnormalities should be considered the cause of arthrogryposis multiplex congenita in neonates with any of the following characteristics: (1) long for gestational age, (2) abnormal earlobe shape (Figure 153.1 [A]), (3) hyperextensible and transparent skin (Figure 153.1 [B]), (4) blue sclera (Figure 153.2 [A]), and (5) craniosynostosis.

Figure 153.1.— Characteristic findings in patients with arthrogryposis due to cartilage problems. [A] dysplastic ears; [B] hyperelastic skin.

Intelligence is usually normal in patients with arthrogryposis multiplex congenita due to cartilaginous abnormalities. The mechanism that leads to arthrogryposis in patients with cartilaginous abnormalities is joint hyperelasticity combined with the normal restriction from movement imposed by intrauterine life. Arthrogryposis multiplex congenita improves with time. The most common entities that present arthrogryposis multiplex congenita due to cartilaginous abnormalities in the neonatal period are: (1) Beals syndrome, (2) Antley-Bixer syndrome, (3) diastrophic dysplasia, and (4) distal arthrogryposis.

Beals Syndrome
Beals syndrome is a connective tissue disorder linked to a fibrillin locus on chromosome 5q23-31 (FBN2). The most distinguishing features of Beals syndrome are crumpled ears and long slim limbs with long fingers . Patients with Beals syndrome may also have frontal bossing, short necks, spinal deformities, hypoplasia of the calf muscle, metatarsus varus, and talipes equinovarus (Figure 153.2). Arthrogryposis primarily involves the knees, elbows, and hands. Patients with Beals syndrome are neurologically normal. Beals syndrome is an autosomal dominant entity.

Figure 153.2.— Beals syndrome: [A] large forehead and blue sclera; [B] long, arachnoid fingers.