Jan 08, 2018

At 10 months of age, the participant was found to have low muscle tone (hypotonia) and developmental delay. He said his first words at 9 months and has added vocabulary slowly over the years. According to his speech therapist, he has a diagnosis of dysarthria. He began walking at 28 months, but developed a wide and abnormal walk (broad-based gait, gait ataxia). He now walks independently, but becomes tired after about 40 steps (increased muscle fatigability). He has difficulty with coordination and falls frequently (ataxia). However, he is able to eat independently and can follow two step commands.

The participant also has dark birthmarks on his forearms, face, and neck (mosaic hyperpigmented nevi) and light colored birthmarks on his hands and back (café au lait spots). Some of his other symptoms include: middle ear abnormalities (middle ear effusions, recurrent otitis media), and autism spectrum disorder.

• Global developmental delay
• Difficulty controlling voluntary movements (ataxia)
• Wide-based walking (broad-based gait)
• Uncoordinated walking (gait ataxia)
• Fear of loud sounds (phonophobia)
• Repetitive behavior (stereotypic behavior)
• Autistic behavior
• Increased muscle fatigability
• Low muscle tone (muscular hypotonia)
• Brain abnormalities (progressive cerebellar ataxia, mild diffuse cerebral atrophy, brainstem dysplasia, hypoplasia of ventral pons, ill-defined olivary nuclei)
• Abnormal facial shape (frontal bossing, high anterior hairline, prominent glabella)
• Smooth area between nose and upper lip (smooth philtrum)
• Downturned corners of mouth
• Dysarthria
• Wide nasal bridge
• Vertical fold of skin covering inner eye (epicanthus)
• Cupped ear
• Low-set ears turned towards back of the head (low-set, posteriorly rotated ears)
• Recurrent middle ear infections (recurrent otitis media)
• Abnormality of the middle ear (middle ear effusions)
• Widely spaced nipples (wide intermamillary distance)
• Curved ring and pinky finger (clinodactyly of the 4^th and 5^th finger)
• Bilateral tapered fingers
• Dark pigmented birthmarks on forearms, face and neck (mosaic hyperpigmented nevi)
• Light colored birthmarks on back of right hand, left hand, and upper back (café au lait spots)
• Curved right lower leg (right tibial bowing)
• Outward turning of heel (talipes valgus)