The case is a female, Filipino child born at 37 weeks' age of gestation. Her skeletal dysplasia was identified on fetal anomaly scanning during pregnancy and was diagnosed with achondroplasia after birth.
She was the third and youngest child to a 36-year-old mother and a 37-year-old father. She has a healthy and neurotypical older sister and brother. The parents were not consanguineous and have no known genetic abnormalities in their family history. Her birth weight was 1,390 g (less than the third percentile, World Health Organization (WHO)), birth length was 40 cm (less than the third percentile, WHO), and head circumference was 32 cm (third to 15th percentile, WHO). Her physical features at birth were described as having proportionately small frontal bossing and dolichocephaly with infraorbital creases. She had a relatively small thoracic cage, which was proportionate to her size. There were no gross rhizomelia or acromelic shortening of limbs. She had bilateral simian creases, bilateral fifth digit midphalanx hypoplasia, and hypoplastic toenails. External genitalia were grossly female.
Peri-natal care included 17-day confinement in the neonatal intensive care unit for hyperbilirubinemia and antibiotic treatment with amikacin and ampicillin for suspected sepsis. Newborn screening and otoacoustic emission tests were normal. She was breastfed for 2 months, after which she was started on formula milk. She has frequent respiratory infections but does not have a history of recurrent ear infections. She also had an exposure to tuberculosis, which was managed with isoniazid for 6 months. Bone aging reports were normal.
At the age of 6 months, delays in motor, language, socio-emotional, and cognitive development were observed. Her fine motor skills included visually tracking, grasping a rattle, and holding her hands together but not yet regarding and reaching for objects. Her gross motor skills were almost of a newborn wherein she was not able to hold up or lift her head. Her language skills included vocalizations, turning to sounds and voices, and laughing but did not yet imitate speech sounds or babbled. Her personal-social skills included regarding faces and smiling responsively and spontaneously but not yet regarding her own hands or feeding herself. Anthropometric measurements were as follows: body weight was 4,100 g (less than the third percentile, WHO), body length was 53 cm (less than the third percentile, WHO), and head circumference was 42.5 cm (50th percentile, WHO). Physical examination revealed universal hypotonia, with a preference for the right hand.
At the age of 17 months, she had improvements in her developmental skills with more motor imitations, vocalizations, and babbling and the ability to follow simple commands. Physical examination continued to show poor muscle tone, flat foot, and joint laxity. She had difficulty feeding as she choked on solid food and had frequent regurgitation. A gastroenterologist assessed her to have gastroesophageal reflux due to hypotonia. She was advised to have slower, smaller feeding to help in her digestion. The issues with reflux resolved by 30 months of age.
In the next 2 years, the child continued receiving physical, occupational, and speech therapy.  Table 2  presents her developmental skills acquisition. It is compared with the skills acquisition of other children with achondroplasia in a study by Ireland et al.
By the age of 27 months, her parents began noticing her poor social skills such as fleeting eye contact, not turning to her name being called, and not pointing or requesting for her needs. Despite undergoing early intervention services, she continued to demonstrate delays in all developmental domains. A summary of her progress and developmental quotient using the Griffith Mental Development Scales is presented in  Table 1 .
At 39 months, she meets the DSM-5 criteria for autism spectrum disorder, manifested by her delays in communication and social skills. She also presented with repetitive and stereotypic behaviors such as a fascination of shadows and hand flapping and would demonstrate repetitive tapping of objects (i.e., pencil) and her hands against hard surfaces like the table.
The Autism Diagnostic Observation Schedule (ADOS-2), Module 1, was administered at 39 months, and she received an additional diagnosis of autism spectrum disorder. The Autism Diagnostic Observation Schedule is a semi-structured standardized assessment of communication, reciprocal social interaction, play, and imaginative use of materials. Module 1 of the assessment was used, which consisted of 10 activities that focused on playful use of toys and other concrete materials. The child's communication score was 6 (cut-off = 4), and social interaction was 8 (cut-off = 7), which both reached the cut-off for autism.
Management of her developmental delays and behavioral concerns continues to be targeted through speech and language therapies that focus on pre-language skills, pragmatics, and communication of her needs and wants. She also continues occupational therapy and physical therapy to address her motor skills, activities of daily living, and sensory processing concerns. She receives special education with focus on self-regulation and engagement, and behavior modifications to allow her to be involved in learning activities.