The case of one missing boy cast a shadow over a generation of American children. Last week brought another sad reminder 

Etan Patz ... his disappearance woke up New York parents to the dangers of the street. Photograph: Stanley K Patz/AP

Last Thursday, the pickaxes arrived. On Prince Street in the SoHo area of downtown Manhattan, 40 investigators turned up, armed with equipment to dig up a basement beneath what is now a jeans store. To New York's shock, sadness and relief, it was possible that, less than a block from where his parents lived, Etan Patz had been found. 

Almost 30 years before Madeleine McCann disappeared from a hotel bed in Praia da Luz, a six-year-old boy named Etan Patz (pronounced Ay-tahn Pay-ts) walked out of his parents' home in SoHo, wearing his beloved pilot's cap and a corduroy jacket. It was the first time he had been allowed to go to school on his own and his parents, Stanley and Julie, had only relented, reluctantly, after much pleading from their son. It was not until the end of the day that they learned he had never made it to school. He never even boarded the school bus. On 25 May 1979, Etan Patz disappeared and his case sparked as much national attention and ensuing hysteria as Madeleine McCann's would decades later.

The Patz parents have never moved house or changed their phone number, in the hope that, one day, Etan would find his way home. They watched from their window last week as the investigators removed concrete and bricks from the basement of the nearby building which had, according to the New York Post, been used as a play area for local children when Etan was little. They had to listen to the noises of investigators searching for their son's remains while they stayed behind a locked door, still waiting for Etan.

Although Etan himself disappeared, his shadow was long and dark, and all children, including me, who grew up in New York in the late 70s and early 80s lived under it. Stanley Patz was a photographer and pictures of his son – tender, unforgettable and, suddenly, ubiquitous – filled the city. Everyone knew what Etan looked like, but no one would see him again. Even if your parents protected you from the specifics of Etan's disappearance, you felt its ramifications, either through your parents being more vigilant – "His vanishing ushered in the modern era of permanently heightened alert about the dangers of letting children walk the streets alone," as the New York Times put it – or through the new focus on missing children in general.

Putting photos of missing children on the backs of milk cartons was just one of the developments to come out of Etan's disappearance – another was the establishment of National Missing Children's Day on 25 May, the day he vanished – and he, of course, was one of the first children to feature.

As soon as I was old enough to read, I studied the milk carton notices carefully as I ate my breakfast. I would always check to see whether the missing child lived in New York, like I did, whether they had a sister, like I did. The more different they were from me, I'd tell myself, the safer I was.

I remember learning about Etan very well, over my Cheerios. He was from New York. He had a sister. He was Jewish, too. He was born six years before me, but it felt close enough. If the kidnapping of Etan Patz woke up New York parents to the dangers of the street, it taught me that mothers and fathers could not always protect their children, children just like me.

While Stan and Julie Patz have done much to try to prevent other parents from going through what they have suffered, their pursuit for justice for their own son has consisted of nothing but more pain and disappointment. To help him get through the first three years of his son's disappearance, Stan tried to convince himself that Etan had been taken by "a deranged but well-intentioned motherly type [who] was loving Etan somewhere," Lisa R Cohen writes in her 2009 book on the case, After Etan: The Missing Child Case that Held America Captive. This self-sustaining myth soon collapsed and he, along with many others, strongly suspected José Ramos, a drifter who had known one of Etan's babysitters. Ramos admitted in 1982 he had tried to molest the little boy the day he disappeared but insisted he hadn't killed him. Ramos has been in prison since 1987 for other abuses but no one could connect him to Etan's murder, and there was no body in any case. But every year, on Etan's birthday and on the anniversary of his disappearance, Stan sends Ramos a lost child poster of Etan and writes on the back: "What did you do to my little boy?"

Last week, a police dog showed signs of smelling human remains in the basement and another suspect, a local handyman who had known Etan, emerged when he blurted out: "What if the body was moved?" But by Tuesday, there was disappointment, again. Nothing had been found in the basement. The investigators went home. Stan and Julie stayed inside.

According to the US Department of Justice, 2,185 children are reported missing in America every single day. In a fairer world, all would get the attention that Etan did. In a fair world, none would vanish at all. For whatever reason, one case occasionally emerges that haunts a generation. While the other children of their era grow up, become adults and have children of their own, those lost few are frozen forever in the photographs their desperate parents release to the media, their toothy childish smiles the only replies to unanswered questions.