Cassian

Cassian met all of his developmental milestones on time. There were no delays and no early concerns. He crawled when expected. He walked when expected. He ran, climbed and explored confidently. He could throw and catch a ball. His motor skills developed steadily.

His speech and social development were equally typical. He babbled, then spoke. He pointed to share interest. He waved goodbye. He clapped proudly. He blew kisses. He followed instructions and responded consistently to his name. He understood what was said to him. He scribbled, played appropriately and engaged with others.

He was affectionate and funny. He understood humour and anticipated reactions. He sought connection and enjoyed interaction. His nursery key worker once remarked that if all children were like him, she would have the easiest job in the world.

Everything was as any parent would hope. His development felt secure. His personality was warm. His future appeared to be unfolding in line with the quiet expectations we hold for our children.

Then, at 28 months old, something shifted.

The first concern came from nursery. They mentioned he had stopped responding to his name and suggested we check his hearing. We were surprised. He had always been receptive and responsive. We assumed it might be selective hearing, a phase.

It was not.

Over the next four months, we watched him unravel.

He lost every word.

His last spoken words were “I love you” and “all done.” Those words remain both significant and haunting to us.

His gestures disappeared. He stopped pointing, waving, clapping and blowing kisses. He stopped drawing. He stopped engaging in the way he once had. He stopped using cutlery and returned to eating with his hands, despite previously feeding himself independently.

During this period, unusual behaviours began to emerge. We noticed long blinks, occasional eye rolling, side staring and brief vacant episodes. At the same time, autistic features appeared. Repetitive movements developed. His play changed and then disappeared. Social reciprocity faded as language and understanding diminished.

This was not a gentle divergence in development. It felt abrupt and total. Established skills vanished while new and unfamiliar symptoms took their place.

His sensory seeking intensified. He chewed obsessively and began placing objects in his mouth, eventually even faeces. He bit. He sought deep pressure. He lost awareness of danger entirely.

Sleep deteriorated. There were long stretches of night waking and episodes of intense dysregulation. At times he would wake screaming as if in severe pain, yet laughing in the same breath. These moments were deeply unsettling and left us unsure what he was experiencing or how to help.

His comprehension appeared to collapse alongside his language.

Today, he looks vacant and disengaged. He does not play with toys, he does not engage in shared play with others, he drifts through spaces without curiosity or apparent purpose. It often feels as though his feet walk this earth but his mind is somewhere distant, somewhere I long desperately to reach.

His cognitive functioning resembles that of a 12 month old. He sticks his fingers into adults’ mouths in a reflexive, infant-like manner. He has no sense of danger. He requires constant supervision. He remains in near perpetual motion and struggles to regulate his body or emotions.

He went from being an unimpaired toddler to being described as profoundly autistic with extremely high needs and global delay.

He now attends a specialist provision. Teachers and carers often comment that he presents differently from other autistic children they have known. They describe him as unique and acknowledge that typical strategies yield limited progress. There is uncertainty about how to help him develop further.

Medically, we had to fight to pursue answers. Finally he underwent genetic testing, metabolic screening, lumbar puncture, MRI imaging and EEG monitoring. Each result was reported as unremarkable.

Unremarkable, in practice, marked the end of investigation.

With the autism diagnosis in place and no identifiable cause found, the medical pathway concluded.

We were told this was likely autism. Yet we struggled to reconcile that explanation alone with what we had witnessed. A child who had developed typically across every domain lost language, comprehension and independence over the course of four months. The timing, abruptness and severity raised questions that felt larger than a diagnostic label.

After extensive research, the description that most closely aligned with our experience was Childhood Disintegrative Disorder, historically used to describe late and profound developmental regression following a period of typical development. However, this diagnosis no longer exists as a separate category. It was removed from diagnostic manuals and absorbed into the broader umbrella of autism spectrum disorder.

At times, the explanation we were given felt less like a fully explored conclusion and more like a default position in the absence of clearer answers. It did not seem grounded in a detailed understanding of what had occurred, but rather in the limits of what could currently be identified or categorised.

Daily life is all consuming. He requires constant supervision and round the clock care. There is no pause, no margin, no moment where vigilance can drop. At the same time, we navigate grief, appointments, paperwork and bureaucracy, advocating repeatedly for support while still searching for medical understanding. We ask for help and are redirected to services that manage needs but do not meaningfully change his developmental trajectory. The interventions provided sustain, but they do not restore. Beneath all of this sits a persistent fear about the future. If his current trajectory does not shift, what will adulthood look like, what will it mean for our family as a whole? 

Special occasions now fill me with a quiet dread. They become reminders of what we once assumed we would share and what has been lost. Each milestone highlights the distance between the life we expected and the reality we now live.

Children who experience catastrophic regression deserve sustained medical curiosity. They deserve research that continues when initial tests are normal. They deserve recognition that unexplained should not mean unexplored.