Maria, the "mystery" girl taken away from a Roma couple in Greece was, DNA evidence has shown, the biological daughter of a Roma couple in Bulgaria. Blonde hair and blue eyes was evidence enough for police in Greece, and in two separate cases in Ireland, to take action. But now that it has emerged that Maria is a Roma child, it is painfully predictable that global interest in her fate will fade. Whatever the legal fate of the couple who have been charged with her abduction, Maria, like other Roma children, will have to navigate her way through life suffering illiteracy, unemployment, and segregation in education.

She will have on average 10 years lower life expectancy than the mainstream population due to hunger and malnutrition, squalid housing and substandard healthcare. If European governments or the wider community are really interested in helping Maria and other Roma children like her, they should start with ensuring access to basic documentation and fundamental rights.

I am Roma and have worked on social justice for many years. The incidents in Greece and Ireland should make it uncomfortably clear to the wider public how quickly Europe can still be whipped into a racist hysteria. They also however illustrate an issue that Roma rights groups have campaigned on for years. The lack of official documentation for Roma – highlighted in the absence of appropriate birth certificates and other papers in Maria's case – is a major reason for Roma exclusion in Europe today.

No country in Europe has accurate statistics for Roma citizens in their official census or other state records. Many Roma do not have birth certificates either; Roma families often forgo registering the birth of a child with local authorities as the cost of obtaining a birth certificate can be prohibitive. Because of this official invisibility, Roma are denied legal protection, public healthcare and the opportunity to enrol their children in school, get a job and register to vote. It also means Roma are at increased risk of human trafficking and miscarriages of justice. If you do not officially exist, it is easy to disappear and be disappeared.

The gaps in official census records for Roma are staggering. A recent census registration campaign carried out by the Open Society Foundations and Roma communities in Hungary achieved a 63% increase in the registered Roma population, from 190,000 to more than 300,000. Huge disparities remain. In Serbia, the 2012 census registered 150,000 Roma; the real number is closer to 400,000.

Some Roma do not officially register their identity due to fear of discrimination. Only six decades ago hatemongers and political leaders sent more than half a million Roma to their deaths for the "collective crime" of simply being Roma; this memory lives on among Roma. Their suspicion of registration is not unfounded. In a recent case in Sweden it was revealed that the police kept a secret and illegal list of more than 4,000 Roma, including many children.

More often, deliberate legal and procedural difficulties put in place by governments restrict Roma from securing proper documentation. A fully documented and registered Roma population means governments must provide fundamental rights such as access to education, healthcare and justice; they must fulfil public job quotas for Roma and include a quota of Roma politicians on electoral rolls. For many governments in Europe, Roma invisibility is politically and economically expedient.

Without official identification documents or legal claims to their property, Roma families are at increased risk of statelessness. A stateless person is not recognised as a citizen by any state. This is important because citizenship is the essential foundation of a person's legal identity. It is your right to have rights. Many Roma in Europe today are trapped in this legal limbo. One example that illustrates the fate of thousands of Roma is Tarmis Urmin, who fled Kosovo in 1999 to a Roma settlement in Belgrade. Urmin had made the 150km trek to Serbia's registration office in a vain attempt to obtain documentation. Because his wife has no documents, his four children cannot get documents either. "When I brought my youngest child to be vaccinated the medical staff demanded 2,000 dinars (about €25)" Urmin recounted. "I had no money and could not afford it. They shouted at me and my family that if we know how to make children we should know how to get documents."

Statelessness exists in western Europe too. Italy is home to thousands of Roma families, many of whom are stateless or at risk of it. They exist in legal limbo, lacking official citizenship for any country, deprived of fundamental civil, political, economic, cultural, and social rights.

Europe's 12 million Roma continue to endure violent attacks, firebombings and serial killings, yet their official invisibility can be just as deadly.

• This article was amended on 29 October 2013. The sentence in paragraph five stating: "In Serbia, the 2012 census registered 190,000 Roma; the real number is closer to 300,000" was changed to "In Serbia, the 2012 census registered 150,000 Roma; the real number is closer to 400,000."